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INSTYTUT TECHNOLOGII DREWNA WOOD TECHNOLOGY INSTITUTE DREWNO PRACE NAUKOWE ● DONIESIENIA KOMUNIKATY WOOD RESEARCH PAPERS ● RESEARCH REPORTS ANNOUNCEMENTS Vol. 56 POZNAŃ 2013 Nr 190 Wydanie publikacji dofinansowane przez Ministerstwo Nauki i Szkolnictwa Wyższego w ramach programu „Index Plus”. The journal is financially supported by Polish Ministry of Science and Higher Educations under the “Index Plus” programme. Recenzenci vol. 56 (Reviewers): Elijah Ajuong, PhD; Prof. Dr. Drs. h.c. rer. silv. habil. Albrecht Bemmann; Myrsini Christou, PhD; Grzegorz Cofta, PhD (Eng); Prof. Claudia Crestini, PhD; Dorota Dziurka, PhD; Benjamin Engler, PhD; Marek Gawor, PhD (Eng); Mark Irle, PhD; Doc. dr. sc. Jaroslav Kljak; Prof. Mgr Juraj Ladomersky, CSc; Elżbieta Mikołajczak, PhD (Eng); Martin Ohlmeyer, PhD; Bartosz Pałubicki, PhD (Eng); Prof. Ing. Ladislav Reinprecht, CSc; Jarosław Szaban, PhD (Eng); Assc. Prof. Maja Szymura-Tyc, PhD; Prof. Ing. Jozef Zajac, CSc Publikacje indeksowane są w bazach danych (Publications are indexed in the databases): Agro – http://agro.icm.edu.pl/agro, Science Citation Index Expanded – http://thomsonreuters.com, BazTech – http://baztech.icm.edu.pl, SCOPUS – http://www.scopus.com, DREWINF – http://www.itd.poznan.pl, The Central European Journal of Social Sciences and Humanities – http://cejsh.icm.edu.pl, Ebsco – www.ebscohost.com Impact Factor (2012): 0,200 Punkty MNiSW (2013): 15 Wersja pierwotna – papierowa The original version – paper Wydawca (Publisher): Instytut Technologii Drewna ul. Winiarska 1, 60-654 Poznań, Polska (Poland) Adres Redakcji (Editor’s address): Instytut Technologii Drewna ul. Winiarska 1, 60-654 Poznań tel.: +48 61 849 24 01, +48 61 849 24 61, fax: +48 61 822 43 72, e-mail: [email protected] © Copyright by Instytut Technologii Drewna w Poznaniu Poznań 2013 ISSN 1644-3985 Projekt okładki (Cover design): Piotr Gołębniak Skład komputerowy (Computer typesetting) oraz druk (Print): Studio Poligrafia, ul. Bułgarska 10, 60-321 Poznań, tel.: +48 61 867 53 72 Nakład (Edition): 520 egz. SPIS TREŚCI – CONTENTS Prace naukowe – Research papers Xue-Fei Zhou: Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects (Katalizowane Co(salen) utlenianie syntetycznego lignino-podobnego polimeru: efekt O2) ................................................................. 5 Dorota Dziurka, Radosław Mirski: Lightweight boards from wood and rape straw particles (Lekkie płyty z wiórów drzewnych i słomy rzepakowej) ....... 19 Agata Stachowiak-Wencek, Włodzimierz Prądzyński: Concentration of volatile organic compounds in the production halls of a selected furniture manufacturing plant (Stężenie lotnych związków organicznych na terenie hal produkcyjnych w wybranym zakładzie przemysłu meblarskiego) .......... 33 Emília Hroncová, Juraj Ladomerský, Christoph Adam: The use of wood from degraded land for carbon sequestration (Wykorzystanie drewna z terenów zdegradowanych do sekwestracji węgla) ..................................................... 51 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski: Strip road impact on selected wood defects of norway spruce (Picea Abies (L.) H. Karst) (Wpływ szlaków operacyjnych na wybrane wady drewna świerka pospolitego (Picea Abies (L.) H. Krast)) .... 63 Agnieszka Jankowska, Paweł Kozakiewicz: The identification of charcoal from archaeological finds in Risan (Montenegro) (Identyfikacja węgli drzewnych ze stanowiska archeologicznego w Risan w Czarnogórze) .......................... 77 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć: Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material in Poland (Biomasa drzewna z upraw drzew szybkorosnących jako alternatywne źródło surowca drzewnego w Polsce) ....................................................................................................... 85 Milena Ratajczak-Mrozek, Magdalena Herbeć: Actors-resources-activities analysis as a basis for Polish furniture network research (Specyfika polskiego przemysłu meblarskiego w ujęciu sieciowym. Perspektywa modelu ARA (aktorzy-zasoby-działania)) .......................................................................... 115 Doniesienia naukowe – Research reports Jacek Wilkowski, Piotr Borysiuk, Jarosław Górski, Paweł Czarniak: Analysis of relative machinability indexes of wood particle boards bonded with waste thermoplastics (Analiza względnych wskaźników skrawalności płyt wiórowych spajanych termoplastami poużytkowymi) .................................. 139 Michał Aniszewski, Piotr Witomski: The state of preservation of archaeological wood uncovered in the Grotto foundations of the retaining wall of the Palace Museum in Wilanów (Stan zachowania drewna archeologicznego odkrytego przy fundamentach Groty muru oporowego Pałacu w Wilanowie) ...... 145 Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.035.01 PRACE NAUKOWE – RESEARCH PAPERS Xue-Fei Zhou1 Co(SALEN)-CATALYSED OXIDATION OF SYNTHETIC LIGNIN-LIKE POLYMER: O2 EFFECTS Molecular oxygen (O2) is widely used as an oxidant in catalytic oxidation. This study was part of a biomimetic oxidation targeted at increasing the use of lignin in the production of chemicals through the application of salen transition metal catalysts. In this work, the catalytic performance of a cobalt-Schiff base catalyst Co(salen) in the presence of an oxidant and a ligand, such as pyridine, was analysed using two polymeric lignin model compounds. Oxidation experiments were carried out in alkaline water (pH 11-12) with the use of H2O2 and atmospheric oxygen (1atm) as oxidants. Co(salen) was an active catalyst, increasing the oxidation rate of the S- and G- type phenolic model polymers. In studies with FTIR, C-13 NMR, and GC-MS spectroscopy, the Co(salen)-catalysed oxidation rate was found to be high in the presence of O2. O2 had effects on the activity of the Co(salen), and it was concluded that the rate of the decomposition of the polymer was increased with the addition of O2. The structure of the lignin model polymers also had an effect on their decomposition. In the form of two CH3O-group polymers (S-type lignin model polymer), the depolymerisation decreased. Irrespective of the polymer (both S- and G- type lignin model polymers), the depolymerisation generated benzaldehydes as the main observed products. The model polymer studies were confirmed to be a useful way to obtain information about the reactions occurring during catalytic oxidation. Keywords: Co(salen), catalyst, catalytic oxidation, lignin model polymer, O2 effect, FTIR, C-13 NMR, GC-MS Xue-Fei Zhou, Kunming University of Science and Technology, Kunming, China; Fudan University, Shanghai, China; Nanjing Forestry University, Nanjing, China; Huaiyin Normal University, Huaian, China; Tianjin University of Science and Technology, Tianjin, China e-mail: [email protected] 6 Xue-Fei Zhou Introduction Co(salen) is a coordination complex derived from the salen ligand and cobalt. The complex reversibly binds O2 to give the oxygenated product, a 1:1 (Co:O2) or a 2:1 (2Co:O2) complex. O2 accepts one electron from each Co2+, forming a superoxide, O2-, bound to Co3+, in the 1:1 complex; O2 accepts one electron from both Co2+, forming a peroxide, O2-2, bound to two Co3+, in the 2:1 complex (fig. 1). This complex is very much like porphyrin but is relatively easy to prepare, cheap, stable in water and small in size, and a number of its derivatives have been widely used as catalysts in a wide variety of useful catalytic reactions. Besides being environmentally more benign, the catalytic oxidation of organic compounds with oxidants, such as dioxygen and hydrogen peroxide, is less economically wasteful than traditional methods and is now an important reaction in both research laboratories and industry [Cozzi 2004; Manickam, Kulandaivelu 2012; Sandaroos et al. 2012]. Fig. 1. Two possible structures for the O2 adduct of Co(salen) Rys. 1. Dwie możliwe struktury adduktu Co(salen) z O2 Salen-catalysed oxidations of organic compounds have been widely studied. These complexes can catalyze the oxidation of substrates that serve as models for lignin phenolic subunits. In the studies of Meguro et al. [1984a; 1984b; 1989], Co(salen) was the most active Co-complex in the oxidation of the phenolic lignin model compound guaiacol. In the O2-oxidation of veratryl alcohol in an alkaline solution, Kervinen et al. [2003] compared several cobalt catalysts, namely Co(salen), Co(α-CH3salen), Co(4-OHsalen), Co(sulfosalen), Co(acacen) and Co(N-Me-salpr). The unsubstituted Co(salen) was the most active and the oxidation was selective at the benzylic position as veratryl aldehyde was the sole product. Reactivity increased linearly with increased O2 pressure. In one study [Sippola 2006], the decomposition of Co(sulfosalen) catalyst was higher in the absence of oxygen. In particular it was demonstrated that they were able to oxidize high Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects 7 yields of lignin model compounds. Arylglycerol-β-aryl ethers, phenylcoumarans and apocynol showed very high conversion values within 30 min [Haikarainen 2005; Rajagopalan et al. 2008; Badamali et al. 2011]. A series of biomimetic oxidations of lignin and a lignin model compound using Co(salen) were successfully studied in our laboratory [Zhou et al. 2011; Zhang, Zhou 2012; Zhou, Liu 2012]. From this and related studies, it was found that salen-type complexes of cobalt had an ability to selectively catalyse oxidation reactions in all experiments and a high catalytic activity was reached with the complex. Co(salen)-catalysed oxidations appeared to allow the creation of high-value products to extend the role of lignin for future biomass and biofuel applications [Crestini et al. 2010; Aresta et al. 2012]. On the basis of these studies, in this paper a synthetic lignin polymer was chosen as the model substrate for further studies on the reactions of lignin and the effect of O2 (O2 effect) because synthetic lignin polymer is more able to resemble natural lignins in their structures, even though it does not have a γ-hydroxymethyl group. Model polymer studies in lignin are important as they can clarify the mechanism occurring during catalytic reaction [Kishimoto et al. 2005; Katahira et al. 2006; Megiatto et al. 2009]. Materials and methods Reagents Co(salen), and 4-hydroxy-3-methoxy-acetophenone, 4-hydroxy-3,5-dimethoxyaceto phenone were obtained from Sigma-Aldrich. 1,4-dioxane, diethyl ether, bromine, K2CO3, DMF, NaBH4, DMSO, NaOH, H2O2, pyridine, O2, CH2Cl2, HCl, and Na2SO4 were purchased from Sinopharm Chemical Reagent Co. Shanghai, China. The chemicals were used as received, without further purification. Synthesis of lignin model polymer Referring to the methods of Kishimoto et al. (2005), the lignin model polymer composed of only the β-O-4 structure was prepared using simple aromatic compounds as starting materials (fig. 2). The commercially available 4-hydroxy-3-methoxy-acetophenone, 4-hydroxy-3, 5-dimethoxyacetophenone was dissolved in anhydrous 1,4-dioxane-diethyl ether (3:4, v/v), adding bromine to the mixture, then kept at 0ºC for 1 hour to prepare the bromide. Adding K2CO3 as the catalyst, the bromide was dissolved in anhydrous DMF, stirred under nitrogen at 50ºC for 3 hours, and polymerized to obtain the given polymer. The given polymer was reduced with NaBH4 in DMSO to obtain the G- and S-type lignin model polymers composed of the β-O-4 structure. The molecular weight (Mw) was determined by gel permeation chromatography (GPC). The Mw of the guaiacyl type polymer (G-type polymer) was 5753, where the value for the syringyl type (S-type poly- 8 Xue-Fei Zhou mer) was 7501. The Mw of the polymers was comparable to that of technical lignin. The chemical structure of the lignin model polymers was characterized by FTIR and 13C-NMR. Fig. 2. Synthesis of S- and G-type lignin model polymers Rys. 2. Synteza modelowych polimerów ligniny typu S- i G- Catalytic experiments residue ( Swith O treatment in H2O2 + pyridine + NaOH + Co(salen) + with O 2 2 13 Gwith O ) 2 FTIR, C -NMR filtration filtrate ( Swith O 2 , Gwith O2 ) GC-MS G, S residue ( S without O treatment in H2O2 + pyridine + NaOH + Co(salen) + without O 2 2 , Gwithout O2) FTIR, 13 C -NMR filtration filtrate ( S without O G without O2) 2, GC-MS , Fig. 3. Programmable route of experiment Rys. 3. Programowalna ścieżka doświadczenia The reactions and reaction conditions of biological systems were mimicked by carrying out oxidation experiments in aqueous solutions. In these experiments, in which the effect of O2 was evaluated in the oxidation of the S- and G-type lignin model polymers in the presence/absence of O2, the standard procedure was to dissolve the lignin model polymers (30 mg), hydrogen peroxide (0.6 mL, 30%) and pyridine (0.96 mL, 0.5 g·L-1) in water (10 mL) and adjust the pH with 0.9 mg NaOH (pH ~12). Following this, the Co(salen) (4.0 mL, 0.5 g·L-1) was added, the reaction flask was evacuated and the ambient oxygen pressure (≥99.5%) was bubbled constantly through the solution at a rate (2.5 cm3/min) low enough to avoid evaporation of the solvent. The mixture was then stirred at 90ºC for 1 hour. The reaction was stopped by cooling the solution to the ambient temperature, after which the reaction mixture was filtered using a fritted glass filter. The final residue (Swith O2, Gwith O2) was collected for FTIR and 13C-NMR analysis. The pH of the filtrate was adjusted to 12 with 2M NaOH and the soluble organic products were extracted with methylene dichloride. The organic phase was separated. The residual filtrate was adjusted to pH 2 with 2M HCl and the soluble organic products were Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects 9 similarily extracted. The two organic phases were merged and dried with sodium sulphate, filtered and finally concentrated to 1mL for reaction product analysis with GC-MS (Swith O2, Gwith O2) (fig. 3). FTIR The FTIR spectra of the lignin model polymers (S, G) and residual lignin model polymers (Swith O2, Gwith O2) obtained from the catalytic experiments were made on a Bruker Tensor 27 spectrophotometer between KBr plates with a 0.1 mm thick layer in wavelength bands from 4000 to 400 cm-1. C-13 NMR spectrometry All 13C-NMR spectra were recorded under quantitative conditions, which were accomplished by using a pulse sequence (inverse-gated) that eliminated the Nuclear Overhauser Effect (NOE) and had a sufficiently long pulse delay, allowing for all nuclei to be fully relaxed before the next pulse. The pulse delay, commonly used for lignin, was 10 seconds. The samples were dissolved in d6-DMSO and the spectra were recorded on Bruker DRX 500 apparatus at 318 K with TMS as the internal reference (δ 0.00) in a 5-mm diameter tube. Some of the acquisition parameters used during the recording of the spectra included 9–15 k number of acquisitions, 90° pulse width (pl = 8 usec, pl 1 = 1.00 db), 222 ppm sweep width, and a 10-second pulse delay. The total acquisition time for recording each spectrum was typically quite long, ranging from 24 to 36 hours. During the processing, a line broadening of 10.0 Hz was used to obtain acceptable line widths. GC-MS The separation and identification of the oxidation products were performed using gas chromatography-mass spectrometry (GC-MS) with an Agilent Technologies HP 6890/5973 system fitted with a fused silica column (HP-INNOWAX, 30 m × 0.25 mm i.d., 0.25 μm film thickness). Each sample was injected into a deactivated glass liner inserted into the GC injection port, using He as the carrier gas (~1.0 mL min-1). The GC oven was programmed from 80ºC (with a 5 min initial delay) to 290ºC (held 40 min) using a 4ºC min-1 temperature ramp. The GC injector and GC-MS interface were maintained at 290ºC. The mass spectrometer was operated in electron ionization mode (EI, 50 eV). Compound identification was performed using GC retention times and by Mainlib database. 10 Xue-Fei Zhou Results and discussion Two types of lignin model polymers were synthesised: a G-type with one electron-donating CH3O-group and S-type with two electron-donating CH3O-groups. The reactions and reaction conditions of biological systems were mimicked by carrying out the oxidation experiments in aqueous solutions. The capability of the Co(salen) complex was tested in the catalytic oxidations of the lignin model polymers, G- and S-type lignin model polymers. In addition, a study was made of the O2 effect of the catalyst at the rate of the oxidation of the lignin model polymers. Polymeric β-O-4 lignin model compounds G- and S-type were the first model compounds to be tested. The oxidation of lignin model polymers lead to the formation of degradation products by the superoxocobalt complex initially formed [Nishinaga, Tomita 1980; Lyons, Stack 2013]. The species formed under these conditions have been spectrally observed in the lignin oxidations [Zhang, Zhou 2012]. The oxidation products consisted of mixtures of benzaldehyde, phenol, and quinone compounds (fig. 6: 7.2 min, 13.9 min, 21.50 min; fig. 7: I, II, III). The main oxidation products were benzaldehydes with good selectivities. Identification was based on the NMR and mass spectra, as well as comparison with authentic samples [Schmidt 2010]. Compounds were formed by a rapid oxidation of α-C alcohol of the polymers. Some minor structural components (compounds II and III) in the oxidation mixtures were formed by other oxidative cleavage, but the amount was usually very low [Zhou et al. 2011]. The results obtained in the oxidations of the lignin model polymers with the use of the Co(salen) complex as a catalyst depended on the oxidant O2 and the structure of the polymer, such as the CH3O-group. The different results obtained in the reactions were compared in the spectra from fig. 4 to fig. 6. The effect of O2 was tested by conducting the oxidations in the presence/absence of O2. According to the results, the catalytic oxidations with the Co(salen) catalyst benefitted from the addition of O2; adding O2 to the reaction mixture in most cases markedly increased the reaction rate. This was because, by adding O2, more of the superoxo complex was formed to more easily oxidise the lignin model polymers. In addition, the degree of degradation in the experiments varied with the CH3O-group of lignin model polymers in the Co(salen)-catalysed oxidations. The G-lignin model polymer gave products with a high degree of degradation, whereas this was low with the S-lignin model polymer, suggesting that the CH3O-group of the polymer has a significant effect on the oxidations. This is probably because the polymer was more stable towards destruction when the second electron-donating CH3O-group was introduced into the ring [Lebo Jr. et al. 2001]. Kervinen et al. [2003] investigated oxidations of 3,4-dimethoxybenzyl alcohol to 3,4-dimethoxybenzaldehyde in aqueous alkaline media using Co(salen) and its derivatives as catalysts, and dioxygen as the terminal oxidant, when the catalyst substrate ratio dropped to 1:5950, a TON (turnover number) as huge as 330 was obtained at ambient dioxygen pressure, the Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects 11 mechanism involved the initial formation of a superoxo complex, which performed a two-electron oxidation of the substrate [Kervinen et al. 2003; Kervinen et al. 2005]. Sippola [2006] found that the best conversion of the substrate to the corresponding aldehyde was 15.1% at atmospheric pressure of dioxygen in the oxidation of 3,4-dimethoxybenzyl alcohol using Co(sulfosalen) as the catalyst. Das and Punniyamurthy [2003], Velusamy and Punniyamurthy [2003] used cobalt and copper complexes of tetrahydrosalen ligand to oxidize benzylic alcohols with H2O2, as dioxygen was found to be an ineffective oxidant with these tetrahydrosalen catalysts. Fig. 4. FTIR spectra of lignin model polymers Rys. 4. Widma FTIR modelowych polimerów ligniny 12 Xue-Fei Zhou For the above oxidations of phenolic lignin model polymers, a reaction mechanism is postulated (fig. 8) [Becker 1980]. First, the catalytically active species removes a hydride ion from the benzylic position. The resulting cation loses a proton, and after tautomerization the oxidised product is obtained. Since the main observed products were aldehydes, the reaction appears to be a two-electron oxidation. Fig. 5. C-13 NMR spectra of lignin model polymers Rys. 5. Widma C-13 NMR modelowych polimerów ligniny Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects Gwith O2 Swith O2 Gwithout O2 Swithout O2 Gwith O2 Swith O2 Gwithout O2 Swithout O2 13 Fig. 6. Total ion chromatograms of S and G samples for GC-MS detection Rys. 6. Chromatogramy całkowitej zawartości jonów próbek S i G przy zastosowaniu detekcji GC-MS Fig. 7. Formation of products I-III by the oxidative cleavage of lignin model polymers Rys. 7. Tworzenie się produktów I-III podczas oksydacyjnego rozkładu modelowych polimerów ligniny 14 Xue-Fei Zhou Fig. 8. Postulated mechanism for the oxidation of lignin model polymers Rys 8. Postulowany mechanizm oksydacji modelowych polimerów ligniny Conclusions A system of Rusing Co(salen) – oxidant for oxidation was investigated. The presented system allowed the oxidation of lignin model polymers, analysing their viability and promoting the production of chemicals. Synthetic lignin-like polymers were synthesized from simple aromatic compounds which offered an additional advantage of enabling the lignin model compounds to resemble natural lignins in their structures. The Co(salen) as the catalyst was capable of catalysing the oxidative degradation of the lignin model polymers. The oxidation of the benzylic positions of both the G- and S-lignin model polymers catalysed by the Co(salen) was studied, and the corresponding aldehydes were identified as the main products with fair yields, especially in the presence of O2. The effects of O2 were to make the reaction smooth and increase the catalytic ability of the Co(salen) within the oxidation. There were some influences of the CH3O-group of the lignin model polymers on the reactions: the presence of the electron-donating CH3O-group in the lignin model polymers was found to decrease the reaction rate. High yields were obtained with the G-type substrate, whereas low yields were obtained with the S-type substrate. The Co(salen) complexes therefore appear to be promising oxidation catalysts for selective transformations of monomeric, dimeric and polymeric lignin model compounds with H2O2 or O2 as terminal oxidants. To confirm the use of a Co(salen) – oxidant system for lignin transformations, further studies on lignin model compounds followed by lignins are needed. Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects 15 References Aresta M., Dibenedetto A., Dumeignil F. [2012]: Biorefinery: From Biomass To Chemicals and Fuels. Water de Gruyter Gmbh & Co. KG, Berlin/Boston Badamali S.K., Luque R., Clark J.H., Breeden S.W. [2011]: Co(salen)/SBA-15 catalysed oxidation of a β-O-4 phenolic dimer under microwave irradiation. Catalysis Communications 12 [11]: 993–995 Becker H.D., Bjork A., Adler E. 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[2006]: Synthesis of β-O-4 type oligomeric lignin model compound by the nucleophilic addition of carbanion to the aldehyde group. Journal of Wood Science 52 [3]: 1–6 Kervinen K., Korpi H., Leskelä M., Repo T. [2003]: Oxidation of veratryl alcohol by molecular oxygen in aqueous solution catalyzed by cobalt salen-type complexes: the effect of reaction conditions. Journal of Molecular Catalysis A: Chemical 203 [1-2]: 9–19 Kervinen K., Korpi H., Mesu J.G., Soulimani F., Repo T., Rieger B., Leskelä M., Weckhuysen B.M. [2005]: Mechanistic insights into the oxidation of veratryl alcohol with Co(salen) and oxygen in aqueous media: an in-situ spectroscopic study. European Journal of Inorganic Chemistry [13]: 2591–2599 Kishimoto T., Uraki Y., Ubukata M. [2005]: Easy synthesis of β-O-4 type lignin related polymers. Organic & Biomolecular Chemistry 3 [6]: 1067–1073 Lebo Jr. S.E., Gargulak J.D., McNally T.J. [2001]: Lignin. In: Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. Lyons C.T., Stack T.D.P. [2013]: Recent advances in phenoxyl radical complexes of salentype ligands as mixed-valent galactose oxidase models. Coordination Chemistry Reviews 257 [2]: 528–540 Manickam R., Kulandaivelu K. [2012]: Meso-tetraphenylporphyriniron (iii) chloride catalyzed oxidation of aniline and its substituents by magnesium monoperoxyphthalate in aqueous acetic acid medium. Polish Journal of Chemical Technology 14 [4]: 35–41 Megiatto J.D. Jr., Cazeils E., Grelier S., Gardrat C., Ham-Pichavant F., Castellan A. [2009]: Synthesis of a lignin polymer model consisting of only phenolic β-O-4 linkages and testing its reactivity under alkaline conditions. Holzforschung 63 [6]: 681–689 Meguro S., Sakai K. [1984a]: Factors affecting oxygen-alkali pulping IV. The effects of oxygencarrying cobalt complexes on guaiacol oxidation. Mokuzai Gakkaishi 30 [1]: 660–667 Meguro S., Sakai K., Imamura H. [1984b]: Factors affecting oxygen-alkali pulping VI. The effect of alkali on the catalytic activity of Co-salen [cobalt(II) bis(salicylidene)ethylenediamine]. Mokuzai Gakkaishi 30 [1]: 1011–1017 Meguro S., Imamura H. [1989]: Factors affecting oxygen-alkali pulping X. Method of estimating the catalytic activity of cobalt complexes in delignification. Mokuzai Gakkaishi 35 [1]: 261–267 Nishinaga A., Tomita H. [1980]: Model catalytic oxygenations with Co(II)—schiff base complexes and the role of cobalt-oxygen complexes in the oxygenation process. Journal of Molecular Catalysis 7 [2]: 179–199 16 Xue-Fei Zhou Rajagopalan B., Cai H., Busch D.H., Subramaniam B. [2008]: The catalytic efficacy of Co(salen) (AL) in O2 oxidation reactions in CO2-expanded solvent media: Axial ligand dependence and substrate selectivity. Catalysis Letters 123 [1-2]: 46–50 Sandaroos R., Goldani M.T., Damavandi S., Mohammadi A. [2012]: Efficient asymmetric Baeyer–Villiger oxidation of prochiral cyclobutanones using new polymer-supported and unsupported chiral Co(salen) complexes. Journal of Chemical Sciences 124 [4]: 871–876 Schmidt J.A. [2010]: Electronic spectroscopy of lignins. In: Lignin and Lignans Advances in Chemistry. Heitner C., Dimmel D. R., Schmidt J. A., Eds.; CRC Press, 49–102 Sippola V. [2006]: Transition Metal-Catalysed Oxidation of Lignin Model Compounds for Oxygen Delignification of Pulp. Unpublished doctoral dissertation, Helsinki University of Technology, Espoo, Finland Velusamy S., Punniyamurthy T. [2003]: Copper(ii)-catalyzed oxidation of alcohols to carbonyl compounds with hydrogen peroxide. European Journal of Organic Chemistry [20]: 3913–3915 Zhang N., Zhou X.-F. [2012]: Salen copper (ii) complex encapsulated in Y zeolite: An effective heterogeneous catalyst for tcf pulp bleaching using peracetic acid. Journal of Molecular Catalysis A: Chemical 365: 66–72 Zhou X.-F., Liu J. [2012]: Co(salen)-catalysed oxidation of synthetic lignin-like polymer: Co(salen) effects. Hemijska Industrija 66 [5]: 685–692 Zhou X.-F., Qin J.-X., Wang S.-R. [2011]: Oxidation of a lignin model compound of benzyl-ether type linkage in water with H2O2 under an oxygen atmosphere catalyzed by Co(salen). Drewno 54 [186]: 15–25 KATALIZOWANE Co(salen) UTLENIANIE SYNTETYCZNEGO LIGNINO-PODOBNEGO POLIMERU: EFEKT O2 Streszczenie Co(salen) to kompleks koordynacyjny stanowiący pochodną ligandu salenowego (disalicylaloetylenodiaminy) i kobaltu. Jego pochodne znajdują zastosowanie jako katalizatory. Przeprowadzono badania nad biomimetycznym utlenianiem ligniny i modelowych związków lignin z wykorzystaniem kompleksu Co(salen). Stwierdzono, że reakcje utleniania katalizowane kompleksu Co(salen) pozwalają na powstania wartościowych produktów, które umożliwią wykorzystanie ligniny w aspekcie przyszłych zastosowań jako biomasa i biopaliwa. W pracy zastosowano dwa syntetyczne polimery ligninowe typu S i G, jako modelowe substraty do dalszych badań nad zachowaniem ligniny w reakcjach utleniania katalizowanych kompleksem Co(salen). Jego katalityczną skuteczność i wpływ O2 analizowano za pomocą spektroskopii FTIR, C-13 NMR i chromatografii GC-MS. Odkryto, że Co(salen) zwiększa stopień utlenienia polimerów typu S i G. Natomiast O2 wpływa na jego aktywność. Stopień rozkładu omawianych dwóch polimerów zwiększa się wraz z dodaniem O2. Struktura polimerów wpływa na ich rozkład. W przypadku polimeru z dwiema grupami CH3O- (typ S) depolimeryzacja zmniejszała się. Niezależnie of typu polimeru (S lub G) w procesie depolimeryzacji tworzyły się znaczne ilości benzaldehydów, jako głównych produktów reakcji, zwłaszcza w obecności O2. Co(salen)-catalysed oxidation of synthetic lignin-like polymer: O2 effects 17 Kompleksy Co(salen) wydają się być obiecującymi katalizatorami utleniania dla selektywnych transformacji syntetycznych lignino-podobnych polimerów z wykorzystaniem O2, jako końcowego (ostatecznego) utleniacza. Efekt O2 zwiększają zdolność katalityczną Co(salen)u w reakcji utleniania. Słowa kluczowe: Co(salen), katalizator, utlenianie katalityczne, model polimeru ligninowego, efekt O2, FTIR, C-13 NMR, GC-MS Acknowledgements This work was financed by the National Natural Science Foundation of P. R. China (No. 21166011, 20766002), the Open Project of State Key Laboratory of Molecular Engineering of Polymers at Fudan University (K2013-09), the Open Project of Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology at Nanjing Forestry University (201320), the Open Project of Jiangsu Key Laboratory for Biomass-based Energy and Enzyme Technology at Huaiyin Normal University (JSBEET1318) and the Open Project of Tianjin Key Laboratory of Pulp and Paper at Tianjin University of Science and Technology (201314). Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.051.02 Dorota Dziurka, Radosław Mirski2 LIGHTWEIGHT BOARDS FROM WOOD AND RAPE STRAW PARTICLES The study investigates the properties of lightweight (350–550 kg/m3) particleboards made using wood or rape particles and with veneers applied to their surfaces. Their suitability for the production of furniture and elements of interior design is discussed. Panels with veneer on their faces were made using a “one shot” pressing cycle. It was found that rape particles may be used for the production of lightweight particleboards, and that they are a good alternative to wood chips. Particleboards made of rape straw, covered with beech veneer during the pressing cycle in order to strengthen their subsurface layers, have better properties than the corresponding wood-chip-based particleboards. However, all the boards, throughout the whole density range, meet the requirements for P2 boards, i.e. boards intended for interior decoration and furniture production (MOR 11 N/mm2, MOE 1600 N/mm2, IB 0.35 N/mm2 according to EN 312). Keywords: particleboard, lightweight boards, rape straw, veneer, mechanical properties Introduction Constant growth in the production and consumption of wood-based boards, used mainly in the construction and furniture industry, has been observed for many years at a global and European level. The development of the furniture industry depends on easy access to timber, the global resources of which are limited. The continuing shortage of wood, its increasing price and the growing competition for this material between manufacturers of boards, the pulp and paper industry, and the energy sector using biomass, means that the demand of the wood-based boards industry for lignocellulosic materials can only be met in the coming years by recourse to the existing potential reserves, such as agriculture, especially the plantations of fast-growing or annual crops. Dorota Dziurka, Poznań University of Life Sciences, Poznań, Poland e-mail: [email protected] Radosław Mirski, Poznań University of Life Sciences, Poznań, Poland e-mail: [email protected] 20 Dorota Dziurka, Radosław Mirski Activities concerning the potential use of annual plants in the production of particleboards and fibreboards have been undertaken for many years. It is estimated that the resources of these plants significantly exceed the demand of the wood-based boards industry for lignocellulosic materials. Although the seasonality of supply, the need for storage, the low bulk density, and other negative aspects should be taken into account when using such materials, they should be considered an additional, but still high quality, resource. In recent years a lot of research projects have been conducted investigating the possibilities of using the waste of such plants as flax [Tröger, Ullrich 1994; Tröger et al. 1998], hemp [Girgoriou et al. 2000], sugar cane, rice straw [Yang et al. 2003], jute, grasses (Miscantus) [Tröger et al. 1998], cotton fibers [Guler, Ozen 2004], sunflower stalks [Khristova et al. 1998], vine prunings [Ntalos, Grigoriou 2002], eucalyptus [Pan et al. 2007], evening primrose [Dukarska et al. 2010, 2012], mustard [Dukarska et al. 2011], Pennsylvanian mallow [Czarnecki et al. 2010], cereal straw [Sampathrajan et al. 1992; Hague 1997; Girgoriou 2000; Bowyer, Stockmann 2001; Pawlicki et al. 2001; Mo et al. 2003; Zhang et al. 2003; Boquillon et al. 2004; Zheng et al. 2007] and even rubberwood [Tongboon et al. 2002], bamboo [Papadopoulos et al. 2004], Scots pine needles [Nemli et al. 2008], and shells of coconuts [Papadopoulos et al. 2002], peanuts [Guler et al. 2008] and almonds [Gürü et al. 2006; Pirayesh, Khazaeian 2012]. The most interesting raw material, from among the wide range of above possibilities, which can be used for the production of particleboards, seems to be the straws of major cereal species, mainly because of their prevalence in any climate. The particular suitability of isocyanate adhesives for the manufacturing of this type of boards is due to the extremely good wettability of the straw surface facilitating the creation of a sufficient number of bonds between the individual particles [Mo et al. 2001; Boquillon et al. 2004]. Studies in this area have shown that straw or straw-chip particleboards produced according to the developed technologies and resinated with pMDI, exhibited higher static bending strength, better hydrostatic properties, and a smoother surface than boards produced from wood chips alone. In the 1960s, the Polish Flaxboard Production Plant “Lenwit” in Witaszyce made its first attempts at manufacturing particleboards using rape straw. It was found that rape straw particles combined with wood chips were good quality materials for the production of particleboards, intended for insulation purposes. They were characterized by higher thermal insulating power, lower hygroscopicity and specific gravity. However, the high costs of material preparation and the lack of appropriate binding agents (with high adhesion forces) prevented the implementation of their regular production. The chemical composition of rape straw is slightly different to wood [Dziurka et al. 2005]. Rape straw contains less cellulose and lignin, but more hemicelluloses and mineral compounds. Cellulose positively affects the mechanical pro- Lightweight boards from wood and rape straw particles 21 perties of the boards, but the content of extraction substances is also important, as they determine the adhesion quality. The content of extraction substances in rape straw is slightly higher than the contents of such substances in wood, although – similarly to wood – they are dispersed throughout its mass. Therefore, in contrast to cereal straws, in which olefin substances are mostly accumulated on the surface and thus hinder resination, they should not have a disadvantageous effect on the gluability of rape straw particles, even if typical polar wood adhesives are applied. Considering the literature data discussed above, it seems that the appropriate legal regulations and promotion of the idea among farmers could make rape straw a relatively easy and quick wood substitute. Traditional particleboards with a mean density ranging from 650 to 720 kg/m3, have been used in the furniture industry for many years. However, in the light of new regulations and tendencies, the high density becomes an unquestionable disadvantage. The EU is expected to shortly introduce regulations, according to which the weight of a package containing elements designed for self-assembly cannot exceed 15 kg. Lightweight wood-based boards have been produced for a long time, and they are commonly used mainly in the construction industry, as insulating and soundproof material. However, due to poor mechanical properties, they have not been widely used for furniture production. The furniture industry is, to a large extent, based on honeycomb boards. Their layered structure with a honeycomb core provides a maximal reduction in weight without diminishing the load capacity, stiffness and other structural features. They are not, however, universal materials, and one of their most significant drawbacks is the need to use specialized machinery and equipment, special hardware and significant expenditure of labor. Given the above, it was decided to investigate the possibility of the production of lightweight particleboards, that were refined by overpressing beech veneer in order to strengthen their subsurface layers. Additionally, in view of the wood deficit persisting over the last few years, it was also decided to assess the suitability of rape particles as an alternative raw material for manufacturing particleboards used for the production of furniture and interior design elements. Materials and methods In the board manufacture, commercial pine chips and rape straw particles obtained as a result of double shredding in a knife shredder were used together with peeled beech veneer with a thickness of 1.7 mm. The moisture content in the raw materials used in the tests was 2.5, 3 and 5.1%. Table 1 presents their basic parameters. 22 Dorota Dziurka, Radosław Mirski Table 1. The basic parameters of the raw materials used for the production of lignocellulosic boards Tabela 1. Podstawowe parametry surowców stosowanych do wytwarzania płyt lignocelulozowych Parameter Formula Parametr Average dimensions Średnie wymiary l, b, a [mm] Rape straw Wood chips Wzór Słoma rzepakowa Wióry drzewne – 15.02 × 1.30 × 0.97 12.45 × 1.87 × 0.83 Slenderness ratio Smukłość λ= l a 15.5 15.0 Flatness Płaskość ψ = b a 1.3 2.3 12.44 8.09 Specific surface Powierzchnia właściwa [m2/kg] Fw = 2 1 1 1 + + ρ 0 l b a l, b, a – length, width, thickness l, b, a – długość, szerokość, grubość Two versions of lightweight wood and rape straw particleboards of densities 550, 500, 450, 400 and 350 kg/m3 were produced: single-layer particleboards and those with improved surfaces by the inclusion of decorative veneers (1.7 mm thick) in the surface layers. The 3-layer sandwich structure was hot-pressed together without applying a separate layer of adhesive to the veneers. The thickness of all the boards was 19 mm. The raw and veneered boards were manufactured under laboratory conditions in 3 replications, applying the following pressing parameters: –– pressing time – 300 s, –– unit pressure – 2.5 N/mm2, –– temperature – 200 ºC, –– resination rate for both wood and rape particle pMDI – 10 %. The properties of the manufactured boards were tested following the respective standards: –– modulus of rigidity (MOR) and modulus of elasticity (MOE) according to EN 310 (parallel and perpendicular to the grain), –– internal bond (IB) according to EN 319, –– swelling in thickness (TS) after 24 h of soaking in water according to EN 317 and water absorption (WA). In order to evaluate the mean value and standard deviation, 12 samples of each board were tested (the total number of samples being 36). Lightweight boards from wood and rape straw particles 23 Additionally, for the veneered boards (550 kg/m3), the density profiles were analyzed (laboratory density profile measuring system GreCon DA-X, measurement resolution 0.02 mm at a rate of 0.05 mm/s). Results and discussion The properties of the wood and rape straw particleboards with reduced density are shown in tables 2 and 3. As might be expected, the reduced density of the particleboards resulted in a lower bending strength and modulus of elasticity. Nevertheless, significantly better results were observed for rape straw particleboards. The strength of the particleboards with a density reduced to 350 kg/m3 as compared to those with a density of 550 kg/m3, was only 18% for the wood chip boards and 32% for the rape straw boards. The modulus of elasticity tests yielded similar results. Adding veneer to the particleboard surfaces greatly improved their properties, and some tests even showed a four-fold increase in strength compared to the raw particleboards (table 3). The veneered boards of either wood or rape particles met the requirements of EN 312 standard for P5 particleboards when the density was 450 kg/m3 or greater (only parallel to the grain). This standard assumes that the bending strength and modulus of elasticity for load-bearing particleboards used in humid conditions should not be lower than 2400 N/mm2 and 16 N/mm2. It should be additionally emphasized, that in respect of these properties, the requirements of this standard were even met by the rape straw particleboards with a reduced density of 350 kg/m3. As could be expected, the bending strength perpendicular to the grain in the surface layers was low due to a very weak natural wood strength in this direction (table 3). As shown by the study results, the manufactured boards displayed good strength perpendicular to the plane of the board. Reducing the density was in fact accompanied by a decrease in strength, but the changes were not as sudden as in the case of the bending strength. It was further observed that the strength of the boards with the lowest density amounted to an average 38% of the strength of the highest density boards for both types of particles. Finishing the board surface with veneer did not improve this property and the strength of those boards was in fact similar to that of the raw boards. 425 (12) 365 (25) 320 (16) 495 (23) 460 (22) 420 (20) 370 (12) 330 (14) 450 400 350 550 500 450 400 350 4.09 (0.6) 5.47 (0.5) 8.37 (0.7) 9.38 (1.3) 12.7 (2.3*) 2.56 (0.4) 3.77 (0.6) 6.65 (0.8) 8.51 (1.7) 14.4 (2.1) MOR fm 900 (110) 1180 (180) 1630 (290) 1970 (70) 2330 (390) Płyta z cząstek rzepaku Raw rape straw board 360 (80) 710 (80) 1270 (90) 1570 (110) 2370 (370) Płyta wiórowa Raw particleboard N/mm2 MOE Em * standard deviation, odchylenie standardowe MOR – modulus of rigidity, fm – wytrzymałość na zginanie MOE – modulus of elasticity, Em – moduł elastyczności IB – internal bond, ft – wytrzymałość na rozciąganie prostopadłe do płaszczyzn płyty TS – thickness swelling, Gt – spęcznienie WA – water absorption, nasiąkliwość 465 (20) * 510 (21 ) 500 Zmierzona Measured 550 kg/m 3 Gęstość * Założona Target Density 0.35 (0.04) 0.45 (0.10) 0.64 (0.09) 0.69 (0.09) 0.82 (0.10) 0.35 (0.08) 0.48 (0.09) 0.62 (0.08) 0.90 (0.09) 1.00 (0.11) IB ft Tabela 2. Mechaniczne i fizyczne właściwości surowych płyt z wiórów drzewnych i cząstek rzepaku Table 2. Mechanical and physical properties of raw particleboard and rape straw boards 12 (1.1) 13 (1.6) 14 (1.3) 14 (2.1) 14 (3.6) 7.0 (1.3) 8.1 (1.4) 9.3 (1.2) 9.6 (1.9) 11 (3.5) TS Gt % 72 (11.3) 68 (9.2) 55 (8.2) 50 (9.7) 49 (8.9) 139 (8.2) 132 (7.6) 115 (6.2) 101 (5.2) 96 (4.8) WA Nasiąkliwość 24 Dorota Dziurka, Radosław Mirski 450 (12) 420 (25) 380 (16) 510 (15*) 465 (19) 425 (17) 360 (18) 320 (12) 450 400 350 550 500 450 400 350 30.8 (0.9) 36.5(1.1) 42.5 (1.2) 47.4 (1.7) 51.0 (1.9) 14.5 (0.8) 24.4 (1.1) 32.4 (1.8) 40.5 (1.5) 49.2 (2.7) MOR fm Veneered particleboard N/mm2 MOR fm 4.93 (0.3) 5.05 (0.5) 6.52 (0.7) 8.85 (1.1) MOE Em 480 (60) 810 (90) 970 (90) 1210 (170) 1620 (280) 5620 (340) 6090 (410) 7120 (210) 6960 (390) 7910 (410) 5.64 (0.6) 6.63 (0.8) 8.17 (1.1) 11.3 (0.9) 13.5 (1.2) 840 (60) 1050 (70) 1340 (190) 1660 (230) 1860 (180) Fornirowana płyta z cząstek rzepaku Veneered rape straw board 4390 (140) 4840 (190) 6010 (250) 6600 (180) 12.2 (1.6) Fornirowana płyta wiórowa 7050 (440) MOE Em * standard deviation, * odchylenie standardowe, MOR – modulus of rigidity, fm – wytrzymałość na zginanie, MOE – modulus of elasticity, Em – moduł elastyczności, II – parallel, ^ – perpendicular to grain, II – równolegle, ^ – prostopadle do przebiegu włókien IB – internal bond, ft – wytrzymałość na rozciąganie prostopadłe do płaszczyzn płyty TS – thickness swelling, Gt – spęcznienie, WA – water absorption, nasiąkliwość 495 (20) 500 Zmierzona 525 (21*) kg/m 3 Measured 550 Założona Target Gęstość Density 0.38 (0.06) 0.49 (0.07) 0.64 (0.09) 0. 76(0.10) 0.85 (0.11) 0.37 (0.07) 0.48 (0.09) 0.66 (0.08) 0.84 (0.10) 0.96 (0.11) IB ft 9 (1.2) 9(1.0) 10 (1.3) 11 (2.0) 13 (3.4) 9 (1.4) 9 (1.3) 11 (1.7) 12 (2.9) 12 (3.6) TS Gt Tabela 3. Mechaniczne i fizyczne właściwości fornirowanych płyt z wiórów drzewnych i cząstek słomy rzepakowej Table 3. Mechanical and physical properties of veneered particle- and rape straw boards % 95 (6.8) 88 (8.3) 82 (8.6) 69 (8.2) 66 (6.0) 120 (5.6) 111 (6.3) 98 (5.8) 921(5.9) 86 (5.3) WA Nasiąkliwość Lightweight boards from wood and rape straw particles 25 26 Dorota Dziurka, Radosław Mirski Summing up, the study results revealed that the manufactured particleboards met the IB strength requirements for P5 boards, regardless of the type of particles and method of surface finishing, with the exception of the lowest density boards (350 kg/m3). As shown in tables 2 and 3, the tensile strength perpendicular to the plane of those boards was higher than 0.45 N/mm2. The tests concerning swelling and water absorption showed that even though the swelling fell with decreasing density, it was accompanied by a significant increase in water absorption. This was due to the more porous structure of the lower density boards, which on the one hand reduced its tendency to swelling, and on the other hand improved its ability to absorb water. As could be expected, applying the veneer to the faces moderated water penetration into the boards, resulting in a reduced water absorption of the refined boards by an average of 12%, compared to the corresponding raw boards. It was found that the rape particles may be used for the production of lightweight particleboards, and that they are a good alternative for wood chips. Particleboards made of rape straw and covered with beech veneer during the pressing cycle in order to strengthen their subsurface layers, had better properties than the corresponding wood-chip-based particleboards. While the rape straw particleboards met the requirements for P5 boards (16 N/mm2 and 2400 N/mm2) concerning their mechanical properties (MOR and MOE parallel to grain) even at the lowest density, the wood chip particleboards met those requirements only down to the density of 450 kg/m3. However, both types of boards with a density of 350 kg/m3 met the requirements for the boards used for interior decoration and furniture production (type P2 – 11 N/mm2 according to EN 312). In the case of the boards intended for furniture production, another important factor was the peeling resistance of the subsurface layers. This feature was particularly important for boards with a surface covered with a veneer during the board manufacturing cycle, without using an additional adhesive layer. Again, better results were obtained for the rape straw boards. The density profiles of the veneered boards presented in fig. 1 showed a clearly visible zone of reduced density at the veneer-board interface in the wood chip particleboards, which would result in a lower peeling resistance of this layer. The density profiles of the rape straw particleboards were quite different. The data presented in fig. 1 clearly showed a significant increase in density at the veneer-board border. It was therefore highly probable that this interface would not be the weakest point of the board. These different density profiles may be due to the fact that the presence of waxes in straws of different origins hinders pMDI penetration, thus allowing for better coverage of their surface with resin [Liu et al. 2004]. This way the surface of the straw particles is covered by a uniform adhesive layer which determines the formation of effective bonds. This fact, combined with the higher plasticity of the rape particles and lower bulk density as compared to the wood chips, resulted in a much higher density of rape straw boards after compression to the same thi- Lightweight boards from wood and rape straw particles 27 ckness. In rape straw boards the contact area of straw particles and veneer significantly increased, which undoubtedly improved their bonds. The situation was different in the case of wood chips. Their structure is dissimilar, more porous as compared to rape straw and they are not covered with waxes [Roll et al. 1990; Roll, Roll 1994; Shi, Gardner 2001]. pMDI penetrated into them, thereby weakening the adhesive-bonded joint between the chips and the veneer, which was reflected in the density profiles. a) thickness, grubość [mm] b) thickness, grubość [mm] Fig. 1. Density profiles of veneered particleboard (a) and rape straw board (b) with density 550 kg/m3 Rys. 1. Profile gęstości fornirowanych płyt z wiórów drzewnych (a) i cząstek rzepaku (b) o gęstości 550 kg/m3 28 Dorota Dziurka, Radosław Mirski Conclusions The conducted studies show that rape particles may be used for the production of lightweight particleboards, and that they are a good quality alternative to wood chips. Particleboards made of rape straw, that were covered with beech veneer during the pressing cycle in order to strengthen their subsurface layers, had better properties than the corresponding wood-chip-based particleboards. The main consumer of wood-based boards is the furniture industry. A wood deficit, persisting for a several years, has triggered the search for and utilisation of new raw materials that thus far have not been considered useful, or have been processed only in small amounts. 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[2001]: Dynamic adhesive wettability of wood. Wood and Fiber Science 33 [1]: 58–68 Tongboon S., Kiatkamjornwong S., Prasassarakich P., Oonjittichai W. [2002]: Particleboard from rubber wood flakes with polymeric MDI binder. Wood and Fiber Science 34 [3]: 391–397 30 Dorota Dziurka, Radosław Mirski Tröger F., Ullrich M. [1994]: Reinforcement of three-layer particleboards with retted flax straw. Holz Roh- und Werkstoff 52 [4]: 230–234 Tröger F., Wegener G., Seemann C. [1998]: Miscanthus and flax as raw material for reinforced particleboards. Industrial Crops Products 82 [2]: 113–121 Yang H.S., Kim D.J., Kim H.J. [2003]: Rice straw-wood particle composite for sound absorbing wooden construction materials. Bioresources Technology 86 [2]: 117–121 Zhang Y., Lu X., Pizzi A., Delmotte L. [2003]: Wheat straw particleboard bonding improvements by enzyme pretreatment. Holz Roh- und Werkstoff 61 [1]: 49–54 Zheng Y., Pan Z., Zhang R., Jenkins B.M., Blunk S. [2007]: Particleboard quality characteristics of saline jose tall wheatgrass and chemical treatment effect. Bioresources Technology 98 [6]: 1304–1310 Lists of standards EN 310 [1993]: Wood-Based Panels. Determination of Modulus of Elasticity in Bending and of Bending Strength EN 312 [2011]: Particleboards – Specifications EN 317 [1993]: Particleboards and Fibreboards. Determination of Swelling in Thickness after Immersion in Water EN 319 [1993]: Particleboards and Fibreboards. Determination of Tensile Strength Perpendicular to the Plane of the Board LEKKIE PŁYTY Z WIÓRÓW DRZEWNYCH I SŁOMY RZEPAKOWEJ Streszczenie Tradycyjne płyty wiórowe, charakteryzujące się średnią gęstością w granicach od 650 do 720 kg/m3, są materiałem od lat stosowanym do produkcji mebli. Jednak w świetle nowych przepisów i trendów wysoka gęstość staje się ich zdecydowaną wadą. Lekkie płyty na bazie drewna są już od dawna produkowane, ale szerokie zastosowanie znajdują przede wszystkim w budownictwie, jako materiał izolacyjno-głuszący. Z uwagi jednakże na niskie parametry wytrzymałościowe dotychczas nie są szeroko stosowane do produkcji mebli. Biorąc to pod uwagę, postanowiono zbadać możliwość wytwarzania lekkich płyt z wiórów drzewnych, które w celu wzmocnienia warstw przypowierzchniowych poddano uszlachetnieniu w procesie prasowania fornirem bukowym. Dodatkowo, uwzględniając utrzymujący się już od kilku lat deficyt drewna, postanowiono również ocenić przydatność do tego celu cząstek rzepaku, jako alternatywnego surowca do wytwarzania płyt, które mogłyby znaleźć zastosowanie do produkcji mebli i elementów wyposażenia wnętrz. Badaniom poddano płyty wiórowe oraz rzepakowe o gęstości 350–550 kg/m3, a uszlachetnianie ich powierzchni przeprowadzono metodą 1-cykliczną, w której dekoracyjny fornir naprasowywano w cyklu wytwarzania płyty. Do zaklejenia obu rodzajów wiórów zastosowano pMDI. Lightweight boards from wood and rape straw particles 31 W wyniku przeprowadzonych badań wykazano, iż możliwe jest zastosowanie do wytwarzania lekkich płyt cząstek rzepaku, które mogą stanowić pełnowartościowy substytut wiórów drzewnych. Wytworzone z nich płyty, które w celu wzmocnienia ich warstw przypowierzchniowych oklejono w cyklu prasowania fornirem bukowym, charakteryzują się lepszymi właściwościami niż analogiczne płyty wiórowe. Rozwój i postęp przemysłu płytowego, oprócz wzrostu ilościowego i polepszenia jakości wyrobów, polega również na wprowadzaniu na rynek zupełnie nowych produktów o niespotykanym dotychczas poziomie jakości, atrakcyjnych cechach użytkowych i nowych obszarach zastosowań. Dodatkowym atutem wytworzonych w ramach pracy płyt jest ich znacznie obniżona gęstość w stosunku do tradycyjnych płyt wiórowych. Lżejsze płyty oznaczają nie tylko lżejsze meble, co jest korzystne dla ich użytkowników, ale także zwiększają konkurencyjność gotowego produktu, dzięki łatwemu i szybkiemu wprowadzaniu najnowszych trendów wzorniczych. W tym stanie rzeczy wydaje się, iż fornirowane płyty z wiórów drzewnych i cząstek rzepaku, ze względu na ich korzystne właściwości, idealnie wpisują się w obowiązujące obecnie trendy. Pozwala to przypuszczać, iż będą one mogły znaleźć zastosowanie jako płyty przeznaczone do wyposażenia wnętrz, łącznie z meblami, gdyż w całym zakresie gęstości spełniają wymagania normy dla tego typu płyt (MOR 11 N/mm2, MOE 1600 N/mm2, IB 0,35 N/mm2 wg EN 312 dla płyt P2). Słowa kluczowe: płyta wiórowa, płyty lekkie, słoma rzepakowa, fornir, właściwości mechaniczne Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.043.03 Agata Stachowiak-Wencek, Włodzimierz Prądzyński3 CONCENTRATION OF VOLATILE ORGANIC COMPOUNDS IN THE PRODUCTION HALLS OF A SELECTED FURNITURE MANUFACTURING PLANT The aim of this study was to determine the concentrations of volatile organic compounds found in the air in five production halls at a furniture manufacturing plant. Tests were performed in production halls, where machining operations were performed both on wood and wood-based materials, in shop halls in which surface-finishing operations were performed, as well as a finished goods warehouse. A Tenax TA synthetic sorbent was used to adsorb compounds found in the air. Volatile substances were analysed by gas chromatography combined with mass spectrometry and thermal desorption. It was found that the microclimate in the examined production halls varied. Differences were observed not only in the type of compounds detected in the shop halls, but also in their amounts. The analysed air contained a broad spectrum of volatile compounds, mainly alcohols, glycols, aromatic hydrocarbons, aldehydes, esters and terpenes. The total concentration of volatile organic compounds (TVOC) found in the air in the examined production halls varied within a very broad range from 795 to 5113 µg/m3. The concentrations of volatile organic compounds identified in the production halls were markedly lower than those specified by Polish legal regulations - the Ordinance of the Minister of Labour and Social Policy of 2002 (with later amendments). Keywords: volatile organic compounds, air pollution, furniture industry, gas chromatography with mass spectrometry and thermal desorption (GC/MS/TD) Introduction We are exposed to dust, pollen, fungal and mould spores, as well as chemical pollutants, released by construction materials and interior design elements. It is difficult to reliably define which of the air pollutants found indoors cause only discomfort and which may lead to disease. Sick building syndrome (SBS) has been Agata Stachowiak-Wencek, Poznan University of Life Sciences, Poznan, Poland [email protected] Włodzimierz Prądzyński, Poznań University of Life Sciences, Poznan, Poland [email protected] 34 Agata Stachowiak-Wencek, Włodzimierz Prądzyński discussed for years. Occupants of many facilities suffer from headaches, irritation of the eyes, nose and throat, attention span problems and/or fatigue. Mølhave [2003] presented the range of health effects caused by pollutions pollutants found in indoor air (table 1). An interesting point is that most symptoms disappear upon leaving the building. Their causes are complex, but one of them is connected with the presence of chemicals in the air. Agents suspected of causing ‘sick building’ symptoms include, for example, volatile organic compounds. Studies have shown that indoor air typically contains higher concentrations of pollutants than outdoor air [Andersson et al. 1997; Brinke et al. 1998; Wargocki et al. 1999; Mølhave 2003; Nielsen et al. 2007]. According to analyses conducted by the Environmental Protection Agency (EPA), the concentration of air pollutants inside buildings may be from 2 to 5 times greater than outdoor air. Table 1. Classes of health effects found indoors [Mølhave 2003] Tabela 1. Efekty zdrowotne spotykane w pomieszczeniach [Mølhave 2003] Health effect Symptoms of the disease Efekty zdrowotne Objawy chorobowe Asthma Immune effects and other hypersensitivity Efekty immunologiczne i inna nadwrażliwość Astma Allergy Alegria Non-specific hypersensitivity Nadwrażliwość niesprecyzowana Respiratory effects (other than immunological) – Efekty dróg oddechowych (inne niż immunologiczne) Cancer Cellular effects Efekty komórkowe Rak Other cellular effects including affecting reproduction Inne efekty komórkowe, w tym oddziałujące na rozrodczość Odor Neurogenic and sensory effects Efekty neurogenne i sensoryczne Zapach Irritation Podrażnienie Neurotoxic symptoms Objawy neurogenne Cardiovascular effects Wpływ na układ krążenia – The quality of air in the workplace is as important as that of the air at home. Studies presenting the results of air analyses conducted at industrial or commercial facilities have indicated that air may contain several pollutants [Rufus et al. 2001a, b; Lee et al. 2002; Wu et al. 2004; Loh et al. 2006; Eklund et al. 2008]. Concentration of volatile organic compounds in the production halls of a selected furniture ... 35 However, air in industrial plants may be of particular importance. Technological operations performed at production plants and the materials used obviously have a significant effect on the microclimate of production halls and air polluted with volatile substances. World literature presents to a limited extent studies concerning VOC emissions and air pollution in industrial facilities, particularly the wood industry. When such analyses have been reported, they have typically concerned VOC emissions from materials used in the production process or finished products [Salthammer 1997; Salthammer et al. 1999; Roffael 2006; Ohlmeyer et al. 2008; Kirkeskov et al. 2009; Stachowiak-Wencek 2012]. In the wood industry, the air within production halls, paint shops, assembly rooms, warehouses or grinding shops may contain an extensive spectrum of compounds harmful to human health due to the operations performed there. In the wood industry, volatile substances are emitted not only from finishing materials or binders, but also the basic raw material, i.e. wood. A toxicological evaluation of substances may be performed on the basis of the relation between dose and effects [AgBB 2012]. The U.S. Environmental Protection Agency (U.S. EPA) generally uses reference concentrations (RfCs) to assess the risks from exposure to toxic substances for non-cancer effects. RfCs are supposed to represent lifetime inhalation with minimal appreciable risk. Frequently, a NO(A)EL [“no observed (adverse) effect level”, i.e., the highest exposure level showing no significant effect of exposure] or LO(A)EL [“lowest observed (adverse) exposure level”, showing such an effect], is used to calculate the RfCs [Mølhave 2003]. The most comprehensive evaluation system available for the workplace area is in the form of occupational exposure limit values (OELs) [AgBB 2012]. Occupational exposure limits have been developed in many countries for airborne exposure to gases, vapours and particulates. In Poland, occupational exposure limits for airborne toxic substances have been determined by the Ordinance of the Minister of Labour and Social Policy on the Maximum Admissible Concentrations and Intensities of Harmful to Health Agents in the Working Environment. The official version was published in Dziennik Ustaw 2002, No. 217, item 1833, and modified subsequently in Dziennik Ustaw 2005, No. 212, item 1769; Dziennik Ustaw 2007, No. 161, item 1142; Dziennik Ustaw 2009, No. 105, item 873 and Dziennik Ustaw 2010, No. 141, item 950). For airborne exposures, there are three types of limits in common use: –– NDS – MAC(TWA): Maximum Admissible Concentration: the time-weighted average concentration for a conventional 8-hour workday and a workweek defined in the Labour Code, to which workers may be exposed during their whole working life, without any adverse effects on their health or that of the next generations, 36 Agata Stachowiak-Wencek, Włodzimierz Prądzyński –– NDSCh – MAC(STEL): Maximum Admissible Short-Term Concentration: the short-term exposure limit is an average concentration, to which workers may be exposed without any adverse health effects if it does not last longer than 15 minutes and does not occur more than twice during a workday, at intervals not shorter than 1 hour, –– NDSP – MAC(C): Maximum Admissible Ceiling Concentration: Ceiling concentration, which because of the threat to workers’ health or life, should not be exceeded even instantaneously [http://www.ilo.org/safework/info/ WCMS_151579/lang--en/index.htm]. The aim of this study was to determine the concentration of volatile organic compounds found in the production halls at a furniture manufacturing plant. The scope of the study comprised quantitative and qualitative analyses of compounds contained in the air. Materials and methods Samples for analyses were collected at a furniture manufacturing plant producing case furniture. The analyses were conducted on the air collected from five production halls, in which different technological operations were performed: –– Production hall 1: mechanical working of wood and wood-based materials, (dimensions: 23 × 41 × 4.5 m); –– Production hall 2: surface finishing operations. Three lacquering booths equipped with dry filters had been installed. The finishing operations were performed using manual pneumatic spray guns, (dimensions: 20 × 15 × 5.3 m); –– Production hall 3: surface finishing of furniture elements. An automated lacquering line had been installed in the production hall, (dimensions: 40 × 20 × 5.2 m); –– Production hall 4: machining operations, including the operation of element grinding after preliminary lacquering with undercoating varnish, preparing the surface for final lacquering, (dimensions: 40 × 59 × 6.5 m); –– Production hall 5: warehouse of finished products, (dimensions: 29 × 34 × 9 m). In each room, the air for the analyses was collected from 5 randomly selected locations. The air for the analyses was collected in glass tubes filled with the Tenax TA solid sorbent at 120 mg (35/60mesh, by Alltech). A volume of 500 ml air was transferred through the sorbent layer at a rate of 50 ml/min. Air was sucked in with a FLEC Air Pump 1001, by Chematec Company. The samples were collected at a height of 1.5 m above floor level. Chromatographic analysis: The volatile organic compounds adsorbed on the sorbent layer were released in a thermal desorber and next they were determined using gas chromatography coupled with mass spectrometry, according to the procedure presented in table 2. Concentration of volatile organic compounds in the production halls of a selected furniture ... 37 Table 2. Operating conditions of the TD/GC/MS Tabela 2. Parametry układu analitycznego TD/GC/MS Elements of the system Parameters Elementy układu Parametry Thermal desorber Termiczny desorber Injector Dozownik Microtrap Mikropułapka Gas chromatograph Chromatograf gazowy Thermal desorber connected to sorption microtrap; Purging gas: argon at 20 m3min-1; Purge time: 5 min Termiczny desorber połączony z pułapką sorpcyjną; Gaz płuczący: argon 20 m3min-1; Czas płukania: 5 min Sorbent: 80 mg Tenax TA/30 mg Carbosieve III; Desorption temperature: 250°C for 90 s Sorbent: 80 mg Tenax TA/30 mg Carbosieve III; Temperatura desorpcji: 250°C przez 90 s TRACE GC, Thermo Quest. Column RTX – 624 Restek Corporation, 60m x 0.32mm ID; Df – 1.8 mm: 6% cyanopropylophenyl, 94% dimethylopolysiloxane Detector Mass spectrometer (SCAN: 10 – 350) Carrier gas Helium: 100 kPa, ~2 cm3min-1 Temperature setting 40°C during 2 min, 7°C min-1 to 200°C, 10°C min-1 to 230°C, 230°C for 20 min Kolumna Detektor Gaz nośny Program temperaturowy RTX – 624 Restek Corporation, 60m x 0,32mm ID; Df – 1,8 μm: 6% cyjanopropylofenyl, 94% dimetylopolisiloksan Spektrometr masowy (SCAN: 10 – 350) Hel: 100 kPa, ~2 cm3min-1 40°C przez 2min, 7°C min-1 do 200°C, 10°C min-1 do 230°C, 230°C przez 20 min Qualitative and quantitative analyses: Compounds were identified by comparing the recorded mass spectra with spectra contained in the NIST MS Search library – program ver. 1.7, and confirmed by referring the mass spectra and retention times of the identified compounds to the spectra and retention times of the appropriate standards. The quantitative analysis of the volatile organic compounds emitted from the investigated surfaces was conducted by adding a reference standard 1-bromo-4-fluorobenzene (Supelco). 38 Agata Stachowiak-Wencek, Włodzimierz Prądzyński Results The results of the analyses are given in fig. 1 and table 3. Fig. 1. Chromatograms of volatile organic compounds present in the air collected from: a) production hall 1; b) production hall 2; c) production hall 3; d) production hall 4; e) production hall 5 Rys. 1. Chromatogramy rozdziału lotnych związków organicznych obecnych w powietrzu pobranym z: a) hali produkcyjnej 1; b) hali produkcyjnej 2; c) hali produkcyjnej 3; d) hali produkcyjnej 4; e) hali produkcyjnej 5 CAS No. 123-86-4 octan n-butylu n-butyl acetate CAS No. 127-18-4 Tetrachloroetylen Tetrachloroethylene CAS No. 108-88-3 Toluen Toluene CAS No. 110-62-3 Pentanal Pentanal CAS No. 71-36-3 1-butanol 1-butanol CAS No. 67-64-1 Aceton Acetone 1 Związek Compound 28 38 – 18 32 – – – 2 Maksymalna Maximum Minimum Minimalna Hala 1 Hall 1 37 – 22 – – – 3 Średnia Mean 141 199 – 197 284 – 225 511 – 4 Maksymalna Maximum Minimum Minimalna Hala 2 Hall 2 179 – 249 – 336 – 5 Średnia Mean 22 37 – 14 41 – 34 55 – 6 Maksymalna Maximum Minimalna Minimum 31 – 29 – 47 – 7 Średnia Mean Wartość Value Hala 3 Hall 3 Stężenie związku 163 245 55 64 353 703 188 296 326 552 298 622 8 Maksymalna Maximum Minimum Hall 4 Hala 4 Minimalna Compound concentration [µg/m3] Tabela 3. Stężenie lotnych związków organicznych występujących w powietrzu na terenie hal Table 3. Concentration of volatile organic compounds found in the air of the production halls 200 62 529 223 412 443 9 Średnia Mean 100 170 30 52 297 408 100 188 278 354 235 387 10 Maksymalna Maximum Minimum Minimalna Hall 5 Hala 5 139 45 335 147 315 307 11 Mean Średnia Concentration of volatile organic compounds in the production halls of a selected furniture ... 39 1 CAS No. 111-76-2 2-butoksyetanol CAS No. 7785-70-8 2-butoxyethanol ά-pinen ά-pinene CAS No. 95-47-6 o-ksylen o-xylene CAS No. 108-65-6 Octan 1-metoksy-2-propylu 1-methoxy-2-propyl acetate CAS No. 106-42-3 CAS No. 108-38-3 m,p-ksylen m,p-xylene CAS No. 100-41-4 Etylobenzen CAS No. 142-96-1 Ethylbenzene eter n-butylu n-butyl ether CAS No. 66-25-1 Heksanal Hexanal Tabela 3. Ciąg dalszy Table 3. Continued 139 509 472 625 – – – – – – 3 100 152 – – – – – – 2 3524 4090 200 290 – 33 40 24 39 – 3806 244 – 38 34 – 71 37 32 38 62 79 5 4 599 701 71 92 – – 623 82 – – 11 5 4 6 8 14 – 19 7 – 14 23 6 901 1899 67 151 31 37 – 162 193 56 88 19 38 152 342 8 1447 101 33 – 171 67 29 287 9 801 1401 87 116 18 25 – 124 187 45 67 – – 10 1091 97 23 – 133 56 – – 11 40 Agata Stachowiak-Wencek, Włodzimierz Prądzyński Średnia TVOC: Mean Maksymalna Maximum Minimalna TVOC: Minimum Σ związków niezidentyfikowanych Σ unidentified compounds CAS No. 138-86-3 Limonen Limonene CAS No. 13466-78-9 3-karen 3-carene CAS No. 5131-66-8 1-butoksy-2-propanol 1 1-butoxy-2-propanol Tabela 3. Ciąg dalszy Table 3. Continued 29 47 – 691 967 795 32 – 16 40 30 45 14 28 3 2 51 67 5 8 32 72 – 4 5113 4526 5717 58 5 56 – 5 169 282 – 15 26 – 6 1079 950 1277 214 – 18 – 7 521 899 22 29 – 15 20 8 4715 3329 6178 671 24 – 16 9 225 342 78 146 23 45 257 371 10 3448 2698 4259 294 97 28 341 11 Concentration of volatile organic compounds in the production halls of a selected furniture ... 41 42 Agata Stachowiak-Wencek, Włodzimierz Prądzyński The total concentration of volatile organic compounds (TVOC) found in the air in the examined production halls varied within a very broad range from 795 to 5113 µg/m3. The highest concentration of volatile organic compounds was found in the air collected from production hall 2 containing 3 spraying booths equipped with dry filters, in which the finishing process of the elements was performed using manual spray guns. The lowest VOC concentration was recorded in production hall 1, in which machining operations on wood and wood-based materials was performed. Relatively low VOC concentrations were also recorded in production hall 3, in which the automated finishing line operated. The concentration of VOCs in production hall 3 was at a medium level amounting to 1079 µg/m3 almost 5 times lower than in the facility (production hall 2), in which the surface finishing process was performed using manual spray guns in lacquering booths. A high VOC concentration was also recorded in the air in production hall 4 and in the warehouse of products (in production hall 5). In production hall 4, in which mechanical working was performed, including e.g. the grinding of elements after lacquering with an undercoating varnish, the VOC concentration was on average 4715 µg/m3. The concentration of VOC in the warehouse of finished products was lower, amounting on average to 3448 µg/m3. In the air collected from the analysed production halls, a broad spectrum of compounds was identified, mainly including alcohols, glycols, aromatic hydrocarbons, aldehydes, esters and terpenes. The narrowest spectrum of volatile organic compounds was found in production hall 1, while it was broadest for production halls 4 and 5. 2-butoxyethanol, was a characteristic compound found in all the production halls. Its concentration varied between production halls, ranging from 509 to 3806 µg/m3. 2-butoxyethanol is a compound emitted from water-borne lacquers [Stachowiak-Wencek, Prądzyński 2011]. As it is given off by company materials, the surface finishing process of furniture products at the discussed plant was carried out 70% using water-borne products, and for the other 30%, using solvent products mainly from the group of polyurethane products, while nitrocellulose products accounted for a slight percentage of the process. As it results from company materials the surface finishing process of furniture products at the discussed plant was performed in 70% using water-borne products, and in the other 30% with solvent products mainly from the group of polyurethane products, while nitrocellulose products accounted for a slight percentage of the process. In all the production halls, analyses also detected toluene, n-butyl acetate and terpenes. The concentration of toluene varied within a very broad range from 22 to 529 µg/m3. The lowest concentration was recorded in production hall 1, in which machining operations were performed, the highest in production hall 4, in which machining operations were also performed, although with the difference that the production hall elements were ground after the first stage of lacquering. A high toluene content was also found in the air from production halls 2 and 5, at 249 Concentration of volatile organic compounds in the production halls of a selected furniture ... 43 and 335 µg/m3, respectively. In production hall 3, in which the lacquering line adapted to the application of water-borne products operated, the concentration of toluene was 29 µg/m3. The concentration of n-butyl acetate in the production halls ranged on average from 31 to 200 µg/m3. The greatest amount of this compound was recorded in production hall 4. In production halls 2 and 3, in which surface finishing was performed, the concentration of n-butyl acetate ranged from 31 to 179 µg/m3. Moreover, in all five production halls the analyses showed the presence of terpenes in the air, mainly α-pinene, 3-carene and limonene, i.e. natural compounds coming from wood. The lowest concentrations of these compounds were detected in production hall 3 (100 µg/m3), while they were highest in production hall 5 (222 µg/m3). In almost all the production halls, except for production hall 1, the presence of 1-butanol was found in the air. Its lowest concentration, amounting to 47 µg/m3, was recorded in production hall 3, in which the lacquering line operated. High concentrations of 1-butanol from 315 to 412 µg/m3 were found in the other three facilities. In the air in production halls 2, 3 and 4, hexanal was also detected. The concentration of hexanal in these facilities ranged from 19 to 287 µg/m3. However, in production halls 3, 4 and 5, ethylbenzene was found. Its concentration varied in range from 5 to 67 µg/m3. In production hall 2, n-butyl ether and 1-methoxy-2-propyl acetate were also detected. These compounds were not found in the other facilities. In turn, acetone, pentanal, tetrachloroethylene and 1-butoxy-2-propanol were recorded only in production halls 4 and 5. Discussion Table 4 presents the occupational exposure limits for substances harmful to the health which were identified in the production halls in the tested furniture plant. Table 4 also includes information concerning the health effects caused. When comparing the recorded quality testing results of the air found in the furniture plant to the occupational exposure limits (both NDS and NDSCh) determined by the Minister of Labour and Social Policy, it may be noted that in the examined production halls the concentrations of the detected compounds were much lower. The admissible levels were not exceeded for any of the identified compounds whose concentrations were determined. For example, the NDS value for 2-butoxyethanol, a compound found in all production halls in the largest quantities, is 98 000 µg/m3. In the production halls, the concentration of this compound ranged from 472 (the minimum value detected in hall 1) to 4090 µg/m3 (the maximum value recorded in hall 2), i.e. it was almost 24 times lower (for the maximum value) than the threshold considered a safe level, which should cause no negative effects on the health of the employees working there. CAS No. 108-88-3 Toluen Toluene CAS No. 110-62-3 Pentanal Pentanal CAS No. 71-36-3 1-butanol 1-butanol CAS No. 67-64-1 Aceton Acetone 1 Związek Compound 3 NDSCh [µg/m3] 100 000 118 000 50 000 200 000 300 000 150 000 600 000 1800 000 2 NDS [µg/m3] – – – – 4 NDSP [µg/m3] Najwyższe dopuszczalne stężenia Occupational exposure limits Podrażnienie oczu, nosa; zmęczenie (słabość, przemęczenie), dezorientacja, euforia, zawroty głowy, bóle głowy; rozszerzenie źrenic, łzawienie, stany lękowe, niepokoju, zmęczenie mięśni, bezsenność, parestezja, zapalenie skóry, wątroby, uszkodzenie nerek Irritation of eyes and nose; lassitude (weakness, exhaustion), confusion, euphoria, dizziness, headaches; dilated pupils, lacrimation, anxiety, muscle fatigue, insomnia; paresthesia; dermatitis; liver damage, kidney damage Podrażnienie oczu, skóry, nosa, gardła Irritation of eyes, skin, nose and throat Podrażnienie oczu, nosa, gardła; bóle głowy, zawroty głowy, senność, zapalenie rogówki, niewyraźne widzenie, łzawienie, światłowstręt, zapalenie skóry, możliwe uszkodzenie nerwów słuchowych, utrata słuchu, depresja ośrodkowego układu nerwowego Irritation of eyes, nose and throat, headaches, dizziness, drowsiness, corneal inflammation, blurred vision, lacrimation, photophobia, dermatitis; possible auditory nerve damage, hearing loss; central nervous system depression Podrażnienie oczu, nosa, gardła; bóle głowy, zawroty głowy, depresja ośrodkowego układu nerwowego Irritation of eyes, nose and throat; headaches, dizziness, central nervous system depression; dermatitis 5 Symptomy Symptoms Tabela 4. Najwyższe dopuszczalne stężenia dla substancji zidentyfikowanych w powietrzu badanych hal produkcyjnych i powodowane przez nie efekty zdrowotne Table 4. Occupational exposure limits for substances identified in the air of the examined production halls and caused health effects 44 Agata Stachowiak-Wencek, Włodzimierz Prądzyński CAS No. 108-65-6 Octan 1-metoksy-2-propylu 1-methoxy-2-propyl acetate CAS No. 108-38-3 CAS No. 106-42-3 m,p-ksylen m,p-xylene CAS No. 100-41-4 Etylobenzen Ethylbenzene CAS No. 142-96-1 Eter n-butylu n-butyl ether CAS No. 66-25-1 Heksanal CAS No. 123-86-4 Hexanal Octan n-butylu n-butyl acetate CAS No. 127-18-4 Tetrachloroetylen Tetrachloroethylene 1 Tabela 4. Ciąg dalszy Table 4. Continued – 100 000 200 000 – – 400 000 – 80 000 40 000 – 950 000 480 000 3 200 000 60 000 2 – – – – – – – 4 Podrażnienie górnych dróg oddechowych, kaszel, zawroty głowy, senność, bóle głowy, nudności, ból gardła, suchość skóry, podrażnienie oczu, zaczerwienienie, ból Irritation of upper respiratory tract, coughing, dizziness, drowsiness, headaches, nausea, sore throat, dry skin, irritation of the eyes, redness, pain. Podrażnienie oczu, skóry, nosa, gardła, zawroty głowy, podniecenie, senność, brak koordynacji ruchów, chwiejny chód, wakuolizacja rogówki, brak łaknienia, nudności, wymioty, bóle brzucha, zapalenie skóry Irritation of eyes, skin, nose and throat; dizziness, excitability, drowsiness, incoordination, staggering gait; corneal vacuolization; anorexia, nausea, vomiting, abdominal pain; dermatitis Podrażnienie oczu, skóry, błon śluzowych, ból głowy, zapalenie skóry, narkoza, śpiączka Irritation of eyes, skin, mucous membrane; headaches; dermatitis; narcosis, coma Podrażnienie górnych dróg oddechowych, kaszel, duszność, wpływ na centralny układ nerwowy, efekt narkotyczny, podrażnienie skóry i oczu, zaczerwienienie, świąd i ból Irritation of upper respiratory tract, coughing, shortness of breath, effect on central nervous system, narcotic effect, irritation of skin and eyes, redness, itching, and pain Podrażnienie oczu, nosa, gardła; bóle głowy, zawroty głowy Irritation of eyes, nose and throat; headaches, dizziness Podrażnienie oczu, skóry, górnych dróg oddechowych, bóle głowy, senność Irritation of eyes, skin and upper respiratory system; headaches, drowsiness, narcosis Podrażnienie oczu, skóry, nosa, gardła, systemu oddechowego, nudności, zawroty głowy, zaburzenia koordynacji, bóle głowy, senność, rumień skóry (zaczerwienienie skóry), uszkodzenie wątroby, (potencjalny zawodowy czynnik rakotwórczy) 5 Irritation of eyes, skin, nose, throatand respiratory system; nausea, dizziness, incoordination; headaches, drowsiness; skin erythema (skin redness); liver damage; (potential occupational carcinogen) Concentration of volatile organic compounds in the production halls of a selected furniture ... 45 – – – – 200 000 – – 3 – – 98 000 – 100 000 2 – – – – – – 4 Podrażnienie oczu, skóry, zaczerwienienie, ból Irritation of eyes and skin, redness, pain Podrażnienie górnych dróg oddechowych, oczu, skóry, alergia Irritation of upper respiratory tract, eyes and skin, allergy Podrażnienie oczu i skóry Irritation of eyes and skin Podrażnienie oczu, skóry, nosa, gardła, hemoliza, krwiomocz, depresja ośrodkowego układu nerwowego, bóle głowy, wymioty Irritation of eyes, skin, nose and throat; hemolysis, hematuria, central nervous system depression, headaches; vomiting Podrażnienie górnych dróg oddechowych, oczu, skóry, alergia, możliwe uszkodzenia lub podrażnienie błony śluzowej Irritation of upper respiratory tract, eyes and skin, allergy, possible damageor irritation of mucous membrane Podrażnienie oczu, skóry, nosa, gardła, zawroty głowy, podniecenie, senność, brak koordynacji ruchów, chwiejny chód, wakuolizacja rogówki, brak łaknienia, nudności, wymioty, bóle brzucha, zapalenie skóry 5 Irritation of eyes, skin, nose and throat; dizziness, excitability, drowsiness, incoordination, staggering gait; corneal vacuolization; anorexia, nausea, vomiting, abdominal pain; dermatitis Źródło: Rozporządzenie Ministra Pracy i Polityki Społecznej [2002], ChemSpider | Search and share chemistry [2013]; PAN Pesticides Database: Chemical Active Ingredient Search [2013]; The National Institute for Occupational Safety and Health (NIOSH) [2013]; Material Safety Data Sheets – Pharmco-Aaper [2013] Chemical Active Ingredient Search [2013]; The National Institute for Occupational Safety and Health (NIOSH) [2013]; Material Safety Data Sheets – Pharmco-Aaper [2013] Source: Rozporządzenie Ministra Pracy i Polityki Społecznej [2002], ChemSpider | Search and share chemistry [2013]; PAN Pesticides Database: CAS No. 138-86-3 Limonen CAS No. 13466-78-9 Limonene 3-karen CAS No. 5131-66-8 3-carene 1-butoksy-2-propanol 1-butoxy-2-propanol CAS No. 111-76-2 2-butoksyetanol 2-butoxyethanol CAS No. 7785-70-8 ά-pinen ά-pinene CAS No. 95-47-6 o-ksylen o-xylene 1 Tabela 4. Ciąg dalszy Table 4. Continued 46 Agata Stachowiak-Wencek, Włodzimierz Prądzyński Concentration of volatile organic compounds in the production halls of a selected furniture ... 47 The low concentrations of the volatile organic compounds found in the air of the examined production halls are most probably a consequence of the furniture surface finishing technology adopted in that production plant. Water-borne products are mostly applied in that plant in furniture surface finishing, such as e.g. UV-hardened products. In hall no. 1, in which the operating lacquering line was equipped with a UV drying tunnel, the concentration of volatile organic compounds was one of the lowest (min. 950 µg/m3, max. 1277 µg/m3, mean 1079 µg/m3). A quantitative assessment of the occupational risk associated with exposure to chemical factors may be conducted only for those substances, for which the occupational exposure limits were specified in the respective regulations. For the relatively large number of identified compounds, these values have not been determined to date. This pertains to such compounds as n-butyl ether, 1-methoxy-2-propyl acetate and 1-butoxy-2-propanol, as well as terpenes - compounds commonly found in wood and wood-based processing plants, i.e. α-pinene, 3-carene and limonene. However, these compounds, as shown in table 4, may have a negative effect on the health of workers. Long-term, repeated exposure and inhalation of these compounds, even at slight concentrations, may cause irritation of the eyes, skin, nose and throat, dizziness, excitability, drowsiness, incoordination, nausea, vomiting, abdominal pain, depression, as well as allergies, and they may irritate the mucous membrane. Moreover, the maximum admissible ceiling concentration (NSDP) values have not been specified for any of the identified compounds. We need to be aware that workers are exposed to VOC not only in the work place, but these compounds are also found in housing facilities. As research has shown, organic pollutant levels in housing facilities may be close to the level detected in the examined production halls [Krause et al. 1987; Wallace et al. 1991; Brown et al. 1994; Wiglusz 2000; Guo et al. 2003]. Conclusions 1. The VOC content in the air in a production hall, in which the manufacturing process was conducted, varied both in terms of the amounts of the compounds contained and their types. 2. The total concentration of all volatile compounds (TVOC) recorded in the tested production halls varied in a very broad range from 795 to 5113 µg/m3. 3. In the air collected from the production halls, a broad spectrum of compounds was detected, mainly alcohols, glycols, aromatic hydrocarbons, aldehydes, esters and terpenes. 4. The application of automated lacquering lines contributed to an improvement in the air quality in the facilities in which this equipment operated. 48 Agata Stachowiak-Wencek, Włodzimierz Prądzyński 5. The concentrations of volatile organic compounds identified in the examined production halls were markedly lower than those specified by the Polish legal regulations – the Ordinance of the Minister of Labour and Social Policy of 2002 (with later amendments). References AgBB (Ausschuss zur gesundheitlichen Bewertung von Bauprodukten) [2012]: Healthrelated Evaluation of Emissions of Volatile Organic Compounds (VOC and SVOC) from Building Products Andersson K., Bakke J.V., Bjørseth O., Bornehag C.G., Clausem G., Hongslo J. K., Kjellman M., Kjaegaard S., Levy F., Mølhave L., Skerfving S., Sundell J. [1997]: TVOC and Health in Non-industrial Indoor Environments. Indoor Air 7 [2]: 78–91 Brinke J.T., Selvin S., Hodgson A.T., Fisk W.J., Mendell M.J., Koshland C.P., Daisey J.M. 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[2011]: Emission of volatile organic compounds (VOC) from waterborne lacquers with different contents of solids. Drewno 54 [186]: 51–63 The National Institute for Occupational Safety and Health (NIOSH) [2013]: http://www.cdc.gov/NIOSH/ [July 2013] Wallace L., Pellizzari E., Wendel C. [1991]: Total organic concentrations in 2700 personal, indoor and outdoor samples collected in the US EPA TEAM studies. Indoor Air 1 [4]: 465–477 Wargocki P., Wyon D.P., Bajk Y.K., Clausen G., Fanger P.O. [1999]: Perceived air quality, sick building syndrome (SBS) symptoms and productivity in an office with two different pollution loads. Indoor Air 9 [3]: 165–179 Wiglusz R. [2000]: Zanieczyszczenie powietrza w budynkach substancjami chemicznymi. Praktyka Budowlana 12: 100–102 Wu C.H., Feng C.T., Lo Y.S., Lin T.Y., Lo J.G. [2004]: Determination of volatile organic compounds in workplace air by multisorbent adsorption/thermal desorption-GC/MS. Chemosphere 56 [1]: 71–80 50 Agata Stachowiak-Wencek, Włodzimierz Prądzyński STĘŻENIE LOTNYCH ZWIĄZKÓW ORGANICZNYCH NA TERENIE HAL PRODUKCYJNYCH W WYBRANYM ZAKŁADZIE PRZEMYSŁU MEBLARSKIEGO Streszczenie Celem pracy było określenie stężenia lotnych związków organicznych występujących w powietrzu na terenie pięciu hal produkcyjnych w zakładzie przemysłu meblarskiego. Badaniu poddano hale, w których przeprowadzano zarówno obróbkę mechaniczną drewna i tworzyw drzewnych, jak i hale, w których wykonywano operacje uszlachetniania powierzchni oraz magazyn wyrobów gotowych. Adsorpcję związków obecnych w powietrzu przeprowadzano na sorbencie syntetycznym Tenax TA. Lotne substancje analizowano techniką chromatografii gazowej w połączeniu ze spektrometrią mas i termiczną desorpcją. Stwierdzono, że mikroklimat badanych hal produkcyjnych był zróżnicowany, tak pod względem rodzaju, jak ilości występujących w nich związków. Całkowite stężenie lotnych związków organicznych zmieniało się w bardzo szerokim zakresie, od 795 do 5113 µg/m3. W badanym powietrzu występowały głównie związki należące do alkoholi, glikoli, węglowodorów aromatycznych, aldehydów estrów i terpenów. Stężenie zidentyfikowanych w halach produkcyjnych lotnych związków organicznych kształtowało się na zdecydowanie niższym poziomie niż to regulują polskie przepisy prawne, rozporządzenie Ministra Pracy i Polityki Socjalnej z 2002 roku (z późniejszymi zmianami). Słowa kluczowe: lotne związki organiczne, zanieczyszczenie powietrza, meblarstwo, chromatografia gazowa ze spektrometrią mas i termiczną desorpcją GC/MS/TD) Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.049.04 Emília Hroncová, Juraj Ladomerský, Christoph Adam4 THE USE OF WOOD FROM DEGRADED LAND FOR CARBON SEQUESTRATION Wood and other biomass have the great potential of decreasing carbon dioxide emissions to the atmosphere, or at least mitigating the speed of the increase in the concentration of carbon dioxide. This paper presents an analysis of the possible use of degraded land – thermal power plant ash ponds – for the growth of fast-growing trees for fuel wood and the subsequent utilization of this fuel wood by means of a verified technique – co-combustion with coal, or a proposed technique – pyrolysis. Pyrolysis of wood with the combustion of pyrolysis gases and carbon sequestration would provide approximately 26% more favorable effects on climate change than the co-combustion of wood in a coal-fired boiler. Keywords: wood, degraded land, co-combustion, pyrolysis, carbon dioxide Introduction In the context of climate change, developed countries are beginning to invest a great deal of effort in the research, development and realization of carbon sequestration techniques. All the techniques thus far implemented are energetically and economically demanding. However, the CO2 concentration in the atmosphere is constantly rising. Theoretical consideration leads to the conclusion, that biomass has a great potential to decrease carbon dioxide emissions to the atmosphere, or at least to mitigate the speed of the increase in the concentration of carbon dioxide. According to the Intergovernmental Panel on Climate Change (IPCC), between 1970 and 2004, global emissions of CO2, CH4, N2O, HFCs, PFCs and SF6, weighted by their global warming potential (GWP), increased by 70%, from 28.7 to 49 Gigatonnes of carbon dioxide Emília Hroncová, Matej Bel University, Banská Bystrica, Slovakia; Technical University in Zvolen, Zvolen, Slovakia, e-mail: [email protected] Juraj Ladomerský, Matej Bel University, Banská Bystrica, Slovakia, e-mail: [email protected] Christoph Adam, Technical University in Zvolen, Zvolen, Slovakia e-mail: [email protected] 52 Emília Hroncová, Juraj Ladomerský, Christoph Adam equivalents (GtCO2-eq). The emissions of these gases increased at different rates. CO2 emissions grew by about 80% between 1970 and 2004 and represented 77% of the total anthropogenic GHG emissions in 2004 [IPCC 2007; Moss et al. 2007]. Various scenarios concerning the development of greenhouse gas concentrations in the atmosphere have been created [IPCC 2007]: –– “near-term” scenarios that cover the period up to 2035 –– “long-term” scenarios that cover the period up to 2100 and –– “extended-term” up to 2300. The largest growth in global GHG emissions between 1970 and 2004 came from the energy supply sector (an increase of 145%) [IPCC 2007; Moss et al. 2007]. Energy from biomass has a hugely positive impact on the fulfillment of positive global warming scenarios, because it can be carbon-neutral, or even carbon-negative. At present, a bioenergy supply of 270 EJ, possible on a sustainable basis, can cover almost 50% of the world’s total primary energy demand. Moreover, one hectare of energy willow plantation on polluted lands and lands that are low-yield absorbs up to 200 tons of CO2 from the air over 3 years. An annual bioenergy supply covering the global energy demand in 2050, superseding 1,000 EJ, should be possible with sufficient political support [Ladanai, Vinterbäck 2009]. All sorts of waste wood and biomass can be used as an energy source [Ladomerský 2000; Ladomerský et al. 2003; Hroncová, Ladomerský 2008; Ladomerský, Hroncová 2009; Chrebet et al. 2013]. Research methodology The objective of the research was the analysis of the possible use of degraded land – thermal power plant ash ponds – for the growth of fast-growing trees for fuel wood with the utilization of this wood for electric power generation. Two techniques of energy utilization are compared according to their CO2 abatement; a verified technique – co-combustion with coal, and a proposed technique – pyrolysis, with the combustion of pyrolysis gases and pyrolysis oil. The results of the analysis may be used in strategic decision-making within power plant management, in order to effectively utilize degraded land and decrease GHG emissions as much as possible. The research methodology was based on the carbon and energy balances of the compared techniques. Data used as a basis for the analysis consisted of the preliminary results from the authors’ 2 m3 volume experimental retort, results from the latest pyrolysis technique in the Czech Republic (2013 confidential information) and published data. In terms of CO2 abatement, when comparing the differences between the two techniques for the energy utilization of fast-grown fuel wood, complete life cycle analysis is not necessary for the strategic management of the power plant. Regarding the given techniques and feedstock, emissions of other GHG N2O a CH4 are negligible: 53 The use of wood from degraded land for carbon sequestration –– The highest industrial emissions of N2O are from municipal waste incineration plants. IPCC 2006 set emission factors for N2O from municipal waste incineration plants within the range 8 – 20 g.t-1 MSW. Combustion of pyrolysis gas from biomass pyrolysis will produce much fewer emissions, therefore we can expect an emission factor as low as 1g.t-1, e.g. 0.310 kg CO2-eq. t-1, practically a negligible amount [IPCC 2006; Bailis 2009]. –– Emissions of CH4 are not produced during the combustion of biomass or pyrolysis gas using the best available technique. –– The positive effect of biochar on N2O emission abatement from the soil is not accounted for, because clear quantitative data is not available [Lehmann 2009]. For example, for every ton of biochar applied, 0.394 kg of N2O emissions (CO2-eq = 298 x 0.394 = 117 kg.t-1) to the air will be avoided. Another estimate says that a N2O emission reduction from soil (expressed as CO2eq) contributes to total CO2eq abatement by 4% [Roberts 2010]. This secondary effect slightly improves the impact of pyrolysis on GHG mitigation. For the above-mentioned reasons, this analysis is therefore only focused on CO2 emissions. Assumption and balances A simplified scheme to calculate the substitution of carbon from fossil fuel with biocarbon for the generation of the same amount of electricity: 1 kg C of wood = 1 kg C of coal. In classic power plants, the excess heat is wasted. In new pyrolysis devices, the excess heat is utilized for feedstock drying. Self-usage of electricity and fossil fuels for the process do not directly account for the CO2 balance, but subtracted in energy efficiency. The basic parameters of feedstock and the compared techniques are given in table 1. All the data is given for the dry mass of feedstock. Table 1. Basic parameters for 1 t wood (dry mass) and compared techniques Tabela 1. Podstawowe parametry dla 1 t drewna (sucha masa) i porównywalnych technik Process Parameter Co-combustion of wood in coal fired boiler Pyrolysis with combustion of pyrolysis gas and oil Cinput 490 490 BY 0 175* Proces Współspalanie drewna w kotle opalanym węglem Parametr [kg] * Piroliza ze spalaniem gazu i oleju pirolitycznego Pyrolysis variant with maximum electricity production, but with the lowest CO2 abatement * Wariant pirolizy z maksymalnym wytwarzaniem energii elektrycznej, ale z najmniejszym umniejszeniem CO2 Cinput – carbon input [kg] in 1 t feedstock (dry mass) to co-combustion and pyrolysis Cinput – węgiel wprowadzony [kg] w 1 t wsadu surowcowego (sucha masa) do współspalania i pirolizy BY – biochar yield [kg], the mass of biochar produced from 1 t feedstock BY – wydajność biowęgla [kg], masa biowęgla produkowanego z 1 t wsadu 54 Emília Hroncová, Juraj Ladomerský, Christoph Adam Carbon yield Cbiochar [kg] is defined as the ratio between the mass of carbon in the biochar and the input carbon in the 1 t wood (dry mass). Cbiochar = 0,8 × BY Carbon in biochar for long-term sequestration Clts [kg] is defined as the mass of carbon in the biochar, which remains stable in the soil for hundreds of years. Clts = 0.8 × Cbiochar In the pyrolysis with a low biochar yield, which is on the other hand favorable for electricity generation, the C content in the biochar is a minimum of 80%. The carbon content in the biochar for long-term sequestration can be as high as 80%, which confirms other published data [Lehmann 2009]. The substitution of fossil fuel carbon with biocarbon for the generation of the same amount of electricity from biomass carbon: –– Co-combustion of wood in coal-fired boiler Cfosilco = Cinput × ηCo –– Pyrolysis of wood with pyrolysis gas combustion Cfosilpy = (Cinput − Cbiochar) × ηpy where: ηCo – electric energy efficiency of co-combustion (38%) ηpy – electric energy efficiency of the combustion of pyrolysis gas and pyrolysis oil (35%) CO2 emission reduction by substituting fossil fuels with biofuel in the generation of electricity: –– Co-combustion of wood in a coal-fired boiler CO2 (co) = 3.667 × Cfosilco –– Pyrolysis of wood with pyrolysis gas combustion CO2 (py) = 3.667 × Cfosilpy 3.667 is transformation coefficient CO2/C CO2 emission reduction by sequestration: CO2 (s) = 3.667 × Clts CO2 abatement (∑reduction): –– Co-combustion of wood in a coal-fired boiler = − CO2 (co) –– Slow pyrolysis of wood with pyrolysis gas and oil combustion and biochar sequestration = − CO2 (py) − CO2 (s) Results and discussion The use of degraded land for growing biomass Although worldwide there is still a large unused surface available for growing energy biomass, for example savannas, in developed countries there could arise a problem with the availability of free land for growing energy crops. Farming, transportation and other costs involved in obtaining energy from biomass have to The use of wood from degraded land for carbon sequestration 55 be taken into account. According to Heller, Keoleian and Volk [2003], assuming reasonable biomass transportation distance and energy conversion efficiencies, generating electricity from willow biomass crops could produce 11 units of electricity per unit of fossil energy consumed. A so far unexploited potential for the growth of biomass for energy are various degraded areas, especially around large industrial sites, such as heaps after raw material mining, and sludge beds. Sludge beds contain various types of waste, mainly fly-ash and slag from thermal power plants and heating plants. Some sludge beds are already recultivated, others operate and some are still intensively used. Good examples are sludge beds of large thermal power plants combusting brown or black coal. If a proper care is taken of these sludge beds during their operation, they are sufficiently stable and, after biological recultivation, they are potentially suitable for growing energy crops. The trial growth of energy crops on such sludge beds has started in Slovakia [Tkáč et al. 2011; Majerník et al. 2013]. Short rotation woody crops such as willow, grown in close proximity to a power plant can become a favorable source of energy biomass for co-combustion. In addition, short rotation woody crops also provide other, mostly environmental, benefits including reduced net greenhouse gas. Crops, besides stabilizing the sludge bed by their roots, also take up large amounts of rain water, hence providing sludge bed dewatering. Of course, the use of degraded land around power plants would decrease the biomass transportation distance. In Poland, in most cases, wood biomass is supplied to consumers within 70 to 300 km [Ratajczak et al. 2012]. Degraded land also provides a large space for the disposal of anaerobic digested sewage sludge, which would at the same time serve as fertilizer for short-rotation woody crops. The alkaline environment of a black and brown coal fly-ash sludge bed is a good barrier for the eventual leaching of metals from anaerobic digested sewage sludge to the environment. Bioenergy production on degraded land, such as for example a recultivated slag – fly-ash mixture pond, can even sequester carbon, reduce leaching and increase its stability. From this, it is obvious that the biological recultivation of ash ponds should have a very positive environmental impact on the vicinity of thermal power plants. Willow is a very valuable wood species for this purpose [Walkowiak, Bartkowiak 2012]. The biological recultivation of slag – fly-ash mixture ponds as a complex issue is an unresearched topic thus far. Analysis of biological and thermal processes of wood utilization with respect to CO2 abatement Greenhouse gases originate from organic matter in various biological and thermal processes. The bBasic conversion of biomass in biological and thermal processes can be expressed by these equations: 56 Emília Hroncová, Juraj Ladomerský, Christoph Adam (1) (2) (3) (4) (5) From these equations, basic options for CO2 mitigation using biomass can be determined: 1. Aerobic treatment – the composting of wood biomass together with other biomass. The compost produced can be utilized in two ways, either applied to the soil, or combusted to produce energy. The first variant of compost utilization would contribute to soil quality, but only temporary carbon sequestration would be achieved – only a few years until the full oxidation of CO2. The second variant – composting and compost combustion, does not make sense at first glance. Its purpose is achieved when some other high water content organic matter is co-composted with the wood. Composting can provide intense dewatering, at low cost compared with drying. This way a fuel can be produced with a significantly higher heat content than the heat content of the original materials. The use of energy from this renewable source would eliminate CO2 emissions from coal combustion, thus the contribution of biomass to greenhouse gas emission mitigation can be calculated. For both variants, fast-growing woody crops are suitable, deciduous species being more suitable than coniferous species. 2. Preventing the decomposition of fallen trees in the forest and simply burying wood biomass under a thicker layer of ground [Zeng 2008]. Carbon dioxide bound in wood biomass remains stable in the ground for many centuries. Fast-growing trees could also be used for this purpose. A real economic analysis of this technique has not yet been carried out. Financial benefits could be calculated from the selling of CO2 emissions, or eventually from some kind of subvention for greenhouse gas emission reduction. Technically it is the simplest method of carbon sequestration, but it does not appear to be a competitive way of using fast-growing biomass in comparison with wood utilization in wood industry technology. 3. Anaerobic digestion of wet biomass (but not wood) for biogas generation (CH4 + CO2). The combustion of biogas, mostly in gas Otto engines, generates electricity and the generated heat could possibly be used. The use of energy from this renewable source would eliminate CO2 emissions from coal combu- The use of wood from degraded land for carbon sequestration 57 stion, thus the contribution of biomass to greenhouse gas emission mitigation can be calculated. 4. Economically advantageous, highly effective and technically reliable is the combustion or co-combustion of biomass for heat generation, with the advantage of possible electricity generation. The substitution of fossil fuels with bio fuels contributes to CO2 abatement. 5. The production of biochar by pyrolysis and its application to the soil, with the combustion of volatile substances from pyrolysis for pyrolysis reactor heating. Excess heat should be used to generate electricity and as a heat source. CO2 abatement is achieved by the sequestration of biochar and by the substitution of fossil fuels with bio fuel. The CO2 balance of the energy utilization of fast-growing biomass in power plants For a sustainable climate on Earth, the concentration of atmospheric CO2 will need to be reduced from the current 385 ppm to 350 ppm. Carbon sequestration in agricultural and forestry practices is gaining a lot of attention [Hansen et al. 2008]. Energy utilization of biomass grown on fly-ash ponds is possible in two basic ways: –– the co-combustion of biomass with coal, –– charcoal production by the slow pyrolysis of biomass with the combustion of the gaseous and liquid products of pyrolysis in a cogeneration unit with an internal combustion engine. In the nearest future, it will be interesting to follow the development of new techniques for thermal treatment and the energy utilization of wood, such as flash pyrolysis and torrefaction [Hafsi, Benbouzid 2007; Kuppens et al. 2010; Voets et al. 2011; Witczak et al. 2011; Bridgwater 2012]. The co-combustion of biomass with coal is now becoming relatively common in electricity generation. For electric power producers biochar production and its deposition in the soil is a new method, besides developing CCS methods, for carbon dioxide mitigation. In combined electricity and heat generation with a steam turbine, the overall energy efficiency could be considered as 80%. In combined electricity and heat generation with a cogeneration unit, an overall efficiency of 75% could be achieved. Considering the large amounts of heat generated by coal-fired power plants, it is not possible to effectively utilize heat from biomass. Therefore, only electricity generation will be accounted for. The efficiency of electric energy generation is taken as 38% using a gas turbine and 35% using a cogeneration unit. The results of CO2 balance, reduction and abatement calculated according to the equations given above are in table 2. 58 Emília Hroncová, Juraj Ladomerský, Christoph Adam Table 2. CO2 emission from electricity generation in power plant with co-combustion of coal with biomass in comparison with slow pyrolysis of biomass with combustion of gaseous and oil pyrolysis products in cogeneration unit with internal combustion engine and produced biochar for sequestration. Values are calculated for 1 t of dry wood Tabela 2. Emisja CO2 w procesie wytwarzania energii elektrycznej w elektrowni wykorzystującej współspalanie węgla z biomasą w porównaniu z wolną pirolizą biomasy ze spalaniem gazowych i olejowych produktów pirolizy w urządzeniu do współspalania z wewnętrznym silnikiem spalającym i wyprodukowanym biowęglem do sekwestracji; wartości obliczono dla 1 t suchego drewna Process* Co-combustion wood in coal-fired boiler Pyrolysis with combustion of pyrolysis gas and oil 0 112 186 122 0 411 CO2 (co); CO2 (py) 683 450 CO2 abatement −683 −861 Proces Parameter Parametr [kg] Clts Cfosilco; Cfosilpy CO2 (s) Zmniejszenie CO2 Współspalanie drewna w kotle opalanym węglem Piroliza ze spalaniem gazu i oleju pirolitycznego *Self usage of electricity and fuels in the process not accounted for *Nierozliczone zachodzące w trakcie procesu zużycie energii elektrycznej i paliw na potrzeby własne Summary comparison of co-combustion and pyrolysis of biomass Pyrolysis of biomass grown on a fly-ash pond near a power plant with electricity generation using a cogeneration unit and with carbon sequestration would yield at least a 26% higher CO2 abatement in comparison with the co-combustion of biomass. Biochar production and its application to the soil has several other positive effects. For example, the gradual improvement of the quality and fertility of the pond soil cover, fertilization, and N fixation, which are not evaluated in this paper. Open questions, however, remain to be addressed in separate research projects: –– The impact of sludge bed subsoil on the chemical composition of biomass from contaminated areas [Masu et al. 2012]. –– The chemical composition of biochar from biomass grown on contaminated areas. –– The leachability of eventual problematic substances from biochar in comparison with the leachability of fly-ash from biomass grown on contaminated areas. It is however known that nutrients bound in biochar are released very slowly. The use of wood from degraded land for carbon sequestration 59 Conclusions Great potential to decrease carbon dioxide emissions to the atmosphere, or at least to mitigate the speed of the increase in the concentration of carbon dioxide, is in the biomass, which should be grown on degraded, low quality land. Bioenergy production on degraded land, for example a recultivated slag – fly-ash mixture pond, can in addition sequester carbon, reduce leaching and increase the stability of the pond. The theoretical analysis of CO2 emissions was performed on two techniques – electricity generation in a power plant with the co-combustion of biomass compared with the pyrolysis of biomass with the combustion of gaseous and oil pyrolysis products in a cogeneration unit and biochar for sequestration. The co-combustion of wood in a coal-fired boiler would provide approximately −683 CO2 kg abatement from 1 t of dry wood. Pyrolysis (an emerging technique) of wood with pyrolysis gas combustion and carbon sequestration would provide in the worst case −861 CO2 kg abatement from 1 t of dry wood. This technique would provide at least a 26% more favorable effect on climate change than the co-combustion of wood in a coal-fired boiler. References Bailis R. [2009]: Modeling climate change mitigation from alternative methods of charcoal production in Kenya. Biomass and Bioenergy 33: 1491–1502 Bridgwater A. V. [2012]: Upgrading biomass fast pyrolysis liquids. Environmental Progress & Sustainable Energy 31 [2]: 261–268 Chrebet T., Martinka J., Balog K., Hrusovský I. [2013]: Moment of lignocellulosic material ignition defined by critical mass flow rate. Applied Mechanics and Materials 690–693: 1985–1988 Hafsi S., Benbouzid M. [2007]: Slow and Flash Pyrolysis of Eucalyptus globulus Wood. Research Journal of Applied Sciences 2 [7]: 810–814 Hansen J., Sato M., Kharecha P., Beerling D., Berner R., Masson-Delmotte V., Pagani M., Raymo M., Royer D.L., Zachos J.C. [2008]: Target atmospheric CO2: Where should humanity aim? The Open Atmospheric Science Journal [2]: 217–231 Heller M.C., Keoleian G.A., Volk T. [2003]: Life cycle assessment of a willow bioenergy cropping system. Biomass and Bioenergy [25]: 147–165 Hroncová E., Ladomerský J. [2008]: Emisie zo spaľovania odpadov drevotrieskových dosák (Emissions from the combustion of particleboard waste). Ochrana ovzdušia, Kongres management s.r.o., Bratislava: 31–34 IPCC [2006]: Guidelines for National Greenhouse Gas Inventories. Prepared by the National Greenhouse Gas Inventories Programme, Eggleston H. S., Buendia L., Miwa K., Ngara T. and Tanabe K. (eds). Published: IGES, Japan. Available: http://www.ipcc-nggip.iges.or.jp/ public/2006gl/ IPCC [2007]: Summary for Policymakers. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on 60 Emília Hroncová, Juraj Ladomerský, Christoph Adam Climate Change [B. Metz, O. R. Davidson, P. R. Bosch, R. Dave, L. A. Meyer (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Available: http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-spm.pdf IPPC [2008]: Towards New Scenarios for Analysis of Emissions, Climate Change, Impacts, and Response Strategies. IPPC Geneva Kuppens T., Cornelissen T., Carleer R., Yperman J., Schreurs S., Jans M., Thewys T. [2010]: Economic assessment of flash co-pyrolysis of short rotation coppice and biopolymer waste streams. Journal of Environmental Management 91 [12]: 2736–2747 Ladanai S., Vinterbäck V. [2009]: Global potential of sustainable biomass for energy. SLU, Swedish University of Agricultural Sciences. Department of Energy and Technology, Upsala Swedisch Ladomerský J. [2000]: Emission analysis and minimization from wood waste combustion. Wood Research 45 [4]: 33–44 Ladomerský J., Hroncová E. [2009]: Optimalizácia podmienok spaľovania odpadov drevotrieskových dosák z hľadiska emisií (Optimalization of combustion conditions of particleboard waste from the point of emissions) Ochrana Ovzduší [2]: 14–17 Ladomerský J., Hroncová E., Samešová D. [2003]: Investigation of appropriate conditions for wood waste combustion on basis of emission. Drewno 46 [170]: 90–98 Lehmann J., Joseph S. [2009]: Biochar for environmental management: science and techno-logy [Earthscan] Majerník M., Tkáč M., Bosák M., Haviar S., Szaryszová P. [2012]: Využitie rekultivovaných plôch odkalísk trosko-popolovej zmesi na pestovanie biomasy (Recultivated areas of fly-ash and slag ponds used for growing biomass). Životné prostredie 46 [5]: 258–261 Masu S., Dragomir N., Morariu F., Jurj L., Luminita N., Popescu D. [2012]: The bioaccumulation of heavy metals in barley (Hordeum vulgare L) cultivated on a fly ash dump mixed with compost and natural zeolite materials. Scientific Papers: Animal Science and Biotechnologies 45 [2]: 237 Ratajczak E., Szostak A., Bidzińska G., Herbeć M. [2012]: Demand for wood biomass for energy purposes in Poland by 2015. Drewno 55 [187]: 51–63 Roberts K.G., Gloy B.A., Joseph S., Scott N.R., Lehmann J. [2010]: Life cycle assessment of biochar systems: Estimating the energetic, economic and climate change potential. Environmental Science and Technology 44 [2]: 827–833 Tkáč M., Majerník M., Hronec O., Vilček J., Bosák M. [2011]: Experimentálne overenie možností rekultivácie odkaliska TPZ v SE – EVO Vojany (Experimental verification of possibilities for fly-ash and slag pond reclamation in EVO Vojany, Slovakia). Košice EU PHF [unpublished] Voets T., Kuppens T., Cornelissen T., Thewys T. [2011]: Economics of electricity and heat production by gasification or flash pyrolysis of short rotation coppice in Flanders (Belgium). Biomass and Bioenergy 35 [5]: 1912–1924 Walkowiak M., Bartkowiak M. [2012]: The kinetics of the thermal decomposition of the willow wood (Salix viminalis L.) exposed to the torrefaction process. Drewno 54 [185]: 37–49 Witczak M., Walkowiak M., Cichy W. [2011]: Pre-treatment of biomass by torrefaction – preliminary studies. Drewno 54 [185]: 89–96 Zeng N. [2008]: Carbon sequestration via wood burial. Carbon Balance and Management 3 [1]: 1–12 The use of wood from degraded land for carbon sequestration 61 WYKORZYSTANIE DREWNA Z TERENÓW ZDEGRADOWANYCH DO SEKWESTRACJI WĘGLA Streszczenie Zdegradowane tereny stanowią niewykorzystany potencjał, jeżeli idzie o uprawę biomasy do celów energetycznych. Zaliczają się do nich zwłaszcza obszary znajdujące się na obrzeżach terenów przemysłowych, tj. hałdy pozostałe po wydobyciu surowców czy składowiska szlamów. W przypadku gdy tereny te są wystarczająco stabilne, to po biologicznej rekultywacji potencjalnie będą nadawały się pod uprawę roślin energetycznych. Lesiste uprawy o krótkiej rotacji, takie jak wierzba, uprawiane na wspomnianych składowiskach szlamów w pobliżu elektrowni mogą stać się korzystnym źródłem biomasy przeznaczonej do współspalania. Celem badań była analiza możliwego wykorzystanie terenów zdegradowanych, tj. składowisk popiołu z elektrociepłowni, pod uprawy drzew szybkorosnących, których drewno zostanie przeznaczone do produkcji energii elektrycznej. Porównano dwie techniki wykorzystania do celów energetycznych pod względem zmniejszania przez nie ilości CO2. Pierwszą z nich jest sprawdzona technika współspalania z węglem, natomiast proponowana technika to piroliza ze spalaniem gazów i oleju pirolitycznego. Metodologia badań opiera się na bilansie węgla i energii w porównywanych technikach, który ma strategiczne znaczenie dla zarządzania elektrownią. Do obliczenia substytucji węgla z paliw kopalnych przez biowęgiel koniecznej do wytworzenia tej samej ilości energii elektrycznej użyto uproszczonego schematu: 1 kg C drewna = 1 kg C węgla. Z punktu widzenia wytwarzania energii elektrycznej współspalanie drewna w kotle węglowym jest bardziej pożądane niż piroliza ze spalaniem gazów i oleju pirolitycznego. Z kolei piroliza (rozwijająca się technika) drewna ze spalaniem gazów z pirolizy oraz sekwestracją węgla przyniosłaby przynajmniej o 26% lepsze efekty, jeżeli idzie o zmiany klimatyczne niż współspalanie drewna w kotle opalanym węglem. Słowa kluczowe: drewno, tereny zdegradowane, współspalanie, piroliza, dwutlenek węgla Acknowledgements This work was supported by the Slovak Research and Development Agency within project No. APVV-0353-11 “A proposal and realization of a pilot retort with reduced emissions for charcoal production in marginal zone and the verification of its application”. Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.055.05 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski 5 STRIP ROAD IMPACT ON SELECTED WOOD DEFECTS OF NORWAY SPRUCE (PICEA ABIES (L.) H. KARST) Creating strip roads in second age class stands is an indispensible operation for carrying out thinning. It is especially important in places where there is an intention to do a first thinning using mechanised thinning operations. Felling trees to create strip roads results in altered conditions for the tree growth of neighbouring trees. In particular, this is due to an increase in exposure to sunlight. This can lead to changes in the growth of trees and consequently changes in the morphology of the trunk and the development of defects. The objective of this paper was to analyse the frequency of the presence of particular defects in the structure and shape of spruce in a five-year period after the creation of a strip road. The research was carried out in an artificially regenerated spruce stand within the spruce’s natural, northern habitat in Poland. A 34-year-old stand underwent a systematic thinning scheme which involved the removal of every eighth tree row. The analysis was carried out on trees growing both adjacent to the strip roads (which had a greater growing area around them and greater access to sunlight) as well as trees from further within the stand. Diameter growth was taken in three places: at breast height, in the middle of the trunk between breast height and the base of the crown, as well as at the base of the crown. The average incremental growth, pith eccentricity taper and ovality were calculated. No statistically significant difference in defects between the trees growing by the strip road and those growing further in the stand was observed. Greater taper on mid-tree logs in comparison to butt logs was observed. Insignificant changes in the morphology of the trunks, supports the validity of cutting strip roads in second age class stands. Keywords: wood quality, thinning operation, strip road, wood defects, Norway spruce (Picea abies (L.) H. Karst) Mariusz Bembenek, Poznań University of Life Sciences, Poznan, Poland email: [email protected] Dieter F. Giefing, Poznań University of Life Sciences, Wood Technology Institute, Poznan, Poland email: [email protected] Zbigniew Karaszewski, Wood Technology Institute, Poznan, Poland email: [email protected] Agnieszka Łacka, Poznań University of Life Sciences, Poznan, Poland email: [email protected] Piotr S. Mederski, Poznań University of Life Sciences, Poznan, Poland email: [email protected] 64 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski Introduction The management of multifunctional forests is integrally connected with the ability to access the stand via strip roads, the presence of which is crucial to the effective and balanced management of stands. Creating strip roads is an interference within an ecosystem which may lead to the creation of side effects characterised by a change in the tree microclimate as well as a disruption in the growth and development of trees [Delgado et al. 2007] and it may even lead to the disruption of the integrity of the stand ecosystem [Buckley et al. 2003]. A consequence of this process could be wood of a different quality as compared to wood logged from deeper within the stand away from the strip road [Macdonald, Hubert 2002]. Modern logging technology (not including cable yarders) is directly reliant upon access to stands in the form of strip roads. Strip roads in lowland stands can be established at different stages: 1) during the natural regeneration process tied in with the final felling of the shelter trees, 2) during the first late cleanings with merchantable timber removal [Giefing et al. 2003] as well as 3) during the early, first commercial thinning [Bembenek et al. 2011; 2013a]. The reaction of the trees to the creation of strip roads can be different depending on age and species. Research to date refers generally to the difference in the growth of trees as a result of the creation of strip roads [Matthies, Kremer 1997; Yilmaz et al. 2010]. However, there appears to be a gap in the research into the development of defects in trees growing close to strip roads. The natural reaction of trees to more favourable light conditions is increased growth which can lead to defects in the structure of the tree. This can be seen as an excessive average rate of growth. The felling of trees in order to make a strip road creates better growing conditions for adjacent vegetation. A one-sided increase in light and growing space could, however, generate additional defects: pith eccentricity, taper and ovality. Based on the previously quoted research as well as the acknowledged premise that increased access to light influences trunk shape, a hypothesis was made that trees growing adjacent to a strip road (SR) would develop the aforementioned defects in contrast to the trees growing deeper within the stand (ST). At the same time, it was also assumed that the size of these defects would increase on the higher part of the trees towards the trees’ crown base, where the biggest impact of assimilates on annual ring increments is. Therefore, the aim of this paper was to describe the influence of strip roads on the development of specific tree structure and shape defects. In Poland, under binding technical conditions for plywood, ovality must be taken into consideration, although ovality is also important for sawtimber. All the identified structural defects are also taken into consideration within the quality classification of round wood in accordance with European standard PN-EN 1927-1. 65 Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst) Materials and methods The research was carried out in a premature spruce stand located in a lowland area of northern Poland (54_24’ 57” N, 20_7’ 31” E) in Zaporowo Forest District (Regional Directorate of the State Forests Olsztyn). The area of the stand was 4.96 ha. The stand was created artificially in 1974 by the planting of 3125 trees per hectare with a spacing of 2.5 m between tree rows and 1.5 m between individual trees. The stand was established on post-agricultural land, the soil was rich, over optimal fertility for spruce. Prior to the carrying out of this research, there had been no history of logging in this area. Furthermore, abiotic factors such as wind and snow as well biological factors such as insects, mushrooms and game were found to have not had an influence on the diversity of the area. Annual rainfall within the research area is 750 mm and the average annual temperature is 6–7 degrees Celsius. The vegetation period lasts around 200 days. The average number of days with a strong wind (over 10 m/s) is 40–50 days per year. In early spring 2004, a systematic thinning was carried out on every eighth tree row. The trees were cut with a chainsaw, and the timber was extracted with the Ponsse S15 forwarder (weight 14 t, capacity 12 t) during dry weather conditions. Via this process, 5 m wide strip roads were created, spaced 20 m apart (as measured from axis to axis). After the creation of the strip roads, when 5 annual increments had appeared (in spring 2009), measurements of breast high diameter were taken across the entire stand. Using the established Kraft classification system [Kraft 1884], the biosocial position of each tree was established and the trees were also divided into two groups: 1) trees adjacent to the strip road (SR) and 2) trees from deeper within the wood stand (5–10 m from the axis of the strip roads) (ST) (table 1). Table 1. Tree characteristics (whole stand) Tabela 1. Charakterystyka drzew (cały drzewostan) Localization Lokalizacja Breast height d1.3 Liczba drzew Mean Maximum Minimum Odchylenie standardowe 235 23.6 35 11 5.86 1030 23.9 40 9 6.95 [n·ha-1] Średnia Along strip road (SR) Wzdłuż szlaku operacyjnego (PS) In the stand (ST) W drzewostanie (WD) Standard deviation Pierśnica [cm] Number of trees Maksimum Minimum Next, under the Urich I method, 9 sample trees were taken from each of the two groups (in total 18 trees). Three trees were assigned to each of the three first 66 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski classes of the Kraft classification system. Three sample discs were cut from each tree at three different heights: diameter at breast height (d1.3), halfway between breast height and the crown base (d1/2cb) as well as at the crown base (dcb). Each disc was measured for incremental growth accurate to the nearest 0.01 mm. On the sample trees, the measurement of defects was carried out according to EN 1310 [1997] specifications. The analysis embraced: a) The average annual increment of growth rings (diameter change). Annual growth was measured in four directions (north, south, east and west) for each year in the five-year period after the strip roads were created. Within the same method, the last 5 increments were measured from the last 5 years before the strip roads were created. After carrying out the Bartlett test, the need to carry out logarithmic transformation of some variables emerged. Two-way ANOVA [Searle 1971] was carried out to test the effect of the location (l) and the biosocial class (c). The first experimental factor appears on two levels: l1 – strip road and l2 – wood stand, and the second factor appears on three levels, each corresponding to the three classes of the Kraft classification system (cj, j = 1,2,3). It was assumed that the increments of the growth rings yijk in k’th replication can be written in the following form: yijk = m + li + cj + (lc)ij + eijk (1) Where: m – general mean, li – location effect (factor l), i = 1, 2, cj – j effect (j being the corresponding class in the Kraft classification system) (factor c), j = 1, 2, 3, (lc)ij – second rate interaction effects, eijk – random errors. The post hoc Tukey HSD test was used to compare the significance of the differences among the means. b) Pith eccentricity (x), the distance of the pith from the geometric centre: x = (rN − S − rS ) 2 + (rE −W − rW ) 2 (2) Where: r – radius (mm), E – east, W – west, N – north, S – south. c) Taper (t) (mm m-1): –– sections of the butt log – L1, namely the difference between d1.3 and the diameter d1/2cb divided by the number of meters between the measured diameters, Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst) 67 –– sections of the mid log – L2, namely the difference between d1/2cb and the diameter at the base of the crown dcb also divided by the number of meters between the measured diameters, –– as well as the whole log L3, between d1.3 and dcb, t= d1 − d 2 l (3) Where: d1 – the diameter of the base of the measured section (d1.3 v d1/2cb), d2 – the diameter at the top of the measured section (d1/2cb v dcb). d) Ovality (s): s= d1 − d 2 d1 (4) Where: d1 – the greatest cross section diameter, d2 – the smallest cross section diameter. After checking for normality (Kolmogorov-Smirnov test) and homogeneity of variance (Bartlett test), two-way ANOVA with the use of a model (1) was used to analyse taper, ovality and pith eccentricity. For each of the two tree groups (SR and ST), the average values of taper in the butt log and mid log of the trunk were compared (t test). The same test was administered to compare the taper on the entire log from SR and ST trees. Statistical analysis was carried out using programme R supported by a stats package as well as agricolae [Anonymous 2012]. Results and discussion Rate of Growth Based on the analysis of the measurements, no significant difference was observed in the annual growth rates between all of the trees in the five-year period before the creation of the strip roads. Before the operation, the trees grew in comparable conditions in terms of individual site and soil conditions. A detailed analysis of incremental growth after the creation of the strip road (taking into account the following years and the biosocial position of the trees) revealed a difference in the observed interactions in relation to the location of the samples (fig.1). Additionally, smaller increments (a general growth reduction) after thinning (fig. 1) may suggest harmful effects to the roots or soil compaction by the heavy forwarder (ca. 26 tonnes with load). 68 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski Fig. 1. Trend of mean annual ring width on d1.3 and d1/2cb (SR: trees along strip roads; ST: trees within the stand); rate of growth in A class marked as ≤ 4 mm Rys. 1. Średni przyrost roczny na wysokości pierśnicy i w 1/2 podstawy korony; zaznaczono granicę średniego przyrostu rocznego klasy A ≤ 4 mm The lowest level of interaction was seen at d1.3, with a higher rate of interaction at crown base dcb, whilst the highest was observed in the middle d1/2cb. The increase in living space for the SR trees seems to have had a relatively delayed effect on the growth of the trees, as it was only in the third and fifth year that significantly larger increments were seen in d1/2cb (0.57, p = 0.0447 and 0.96 mm, p = 0.0065 respectively). Earlier, in the first 2 years following the creation of the strip roads, as well as in the fourth year, the trees grew at the same rate as the ST trees. It would appear that the reaction of the spruce to the presence of strip roads is slower than its reaction to wounds it has sustained. Wounds sustained during mechanised thinning operations caused a decrease in radial growth of about 10–50% in the five-year period after they were sustained [Isomäki, Kallio 1974]. The initial lack of uniform changes in the incremental growth of trees following the creation of a strip road can be considered predictable. Giefing et al. [2003] came to similar conclusions carrying out research on pine trees growing adjacent to strip roads of various widths. However, this does not mean that there was no growth reaction in the SR trees. In the initial period, the changes may have been slow due to the time required for the tree to build its crown in the direction of the newly formed gap. Identifying the beginning of the reaction growth process is a complicated task and requires a longer time period, as well as the implementa- 69 Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst) tion of segment regression models consisting of several straights [Jastrzębowski, Klisz 2012]. The higher incremental growth rates in years 3 and 5 after the creation of the strip roads could be the beginning of the formation of wider growths. Borowski [1974] claimed that the greatest incremental growth rates could be observed 9–12 years after the creation of strip roads. The growth increments recorded in the presented research, including those in the last of the five-year period for d1/2cb and dcb, are lower than the normative values for class A (≤ 4 mm). To sum up, it is possible to argue that if the SR spruces were to experience higher incremental growth in later years, their wood may deteriorate in quality. An uneven grain leads to the lumber of the tree cracking and warping. This specific trait (uneven grain) coupled with an increase in average incremental growth requires analysis under PN-EN 1927-1 specifications. Furthermore, with increased annual incremental growth in spruce wood, there is a decrease in the quality of the mechanical properties of the wood, namely the modulus of elasticity in static bending (MOE), maximum crushing strength in compression parallel to the grain (Cmax), as well as to a lesser extent, the modulus of rupture in static bending (MOR) [Zhang 1995]. Eccentric pith Pith eccentricity was present in all the cross-sections, however, the statistical analysis did not confirm the presence of a difference between the biosocial position and the size of these defects in either the SR or the ST trees. The graphical interpretation of the direction of the movement of the pith in relation to the geometric centre of the cross-section revealed certain properties (fig. 2). Table 2. Relative eccentricity (mean) at different heights along the stem; for SR and ST, Kraft classes 1, 2 and 3 Tabela 2. Względne przesunięcie rdzenia (średnie) na badanych wysokościach z uwzględnieniem drzew PS i WD w trzech klasach Krafta Kraft Class Klasa Krafta I Dominant I Górujące II Codominant II Panujące III Intermediate III Współpanujące Trees along strip road (SR) Drzewa przy szlaku (PS) Trees in the stand (ST) Drzewa w drzewostanie (WD) d1.3 d 1/2cb d cb d1.3 d 1/2cb d cb 0.0472 0.0465 0.0402 0.0678 0.0431 0.0545 0.0469 0.0339 0.0290 0.0297 0.0530 0.0443 0.0329 0.0265 0.0461 0.0569 0.0310 0.0487 d1.3 – breast height; d1.3 – pierśnica d1/2cb – halfway up the pruned trunk; pll – połowa oczyszczonej strzały dcb – crown base; dcb – podstawa korony 70 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski Fig. 2. Direction of pith movement (mm) in relation to the geometric centre of the trunk cross-section at d1,3, halfway up the pruned trunk dl/2cb , and at crown base dcb Rys. 2. Kierunek przesunięcia rdzenia (mm) względem geometrycznego środka przekroju pnia na wysokości d1,3 – pierśnica, dl/2cb – połowa oczyszczonej strzały, dcb – podstawa korony Despite the absence of significant differences in the size of the eccentric pith in three cross sections (d1.3, d1/2cb, dcb) of the SR and the ST trees, it was observed that from the crown base dcb of the SR trees, in 8 out of 9 cases the pith had moved in an easterly direction (strip roads run in a north-south direction). At the same time, it must be stressed that of significance to the analysis of the influence of strip roads on the formation of defects is the fact that the piths of these 8 SR trees had moved in the direction of the stand (in the opposite direction to the opening created by the strip road). As the trees were on both sides of the strip road, this suggests that trees are generally under significant influence of the winds dominating in Poland (westerly and north-westerly). The regularity exhibited by dcb is of high interest as the greatest pith eccentricity is usually observed at stump height and diminishes on moving up the stem (as observed on pines) [Mäkinen 1998]. The same author highlights that it is difficult to clearly describe the influence of a single factor in the formation of pith eccentricity. In the aforementioned research papers, the movement of the pith in the lower sections of the stump sample discs was directionless. A more certain order only Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst) 71 occurred at the crown base. This could indicate that the crown, which is developing and growing towards the strip road, will gradually increase the width of its wood in that direction. Liese and Dadswell [1959] observed that wider rings were on the sunny side of the bole, and concluded that directional warming (light) may influence asymmetric growth. The degree of pith eccentricity is an index of the wood quality of the trunk and a result of its strong relationship with the reaction wood [Akachuku, Abolarin 1989; Ren et al. 2006]. The mere development of this defect is associated with several factors analysed both together and separately, such as tree lean, slope and wind [Kellogg, Barber 1981]. The influence of greater living space in the form of a strip road can form an additional element, which over a longer period of time, can contribute to pith eccentricity. Taper Comparing the logs of the trees within the stand with the logs of the trees close to the strip road, no statistically significant differences were observed in terms of ovality. The lack of difference concerns all the researched sections of the wood, irrespective of location and biosocial position. Table 3. Taper of measured logs at different positions along the stem (L1: butt log d1.3 – d1/2cb; L2: mid log d1/2cb – dcb; L3: whole log d1.3 – dcb) Tabela 3. Zbieżystość w poszczególnych kłodach (L1: kłoda odziomkowa – od pierśnicy do połowy długości pomiędzy pierśnicą a podstawą korony; L2: kłoda środkowa – od połowy długości pomiędzy pierśnicą a podstawą korony do podstawy korony; L3: cała kłoda – od pierśnicy do podstawy korony) Localization Lokalizacja SR PS ST WD a Type of log Kłody L1 L2 L3 L1 L2 L3 Taper Zbieżystość (mm m ) 5.27 8.01 6.18 7.52 7.51 6.85 -1 Standard deviation Odchylenie standardowe 1.53 1.72 1.32 3.53 3.15 2.79 L1 vs L2a L3 vs L3b 0.0039** 0.5460 0.9911 n = 18(9L1 + 9L2), b n = 18(9L3(ST) + 9L3(SR)) However, statistically significant differences were observed between the butt log and mid log from the SR trees, p = 0.0039 (table 4). General conclusions cannot be reached here, however, one possible reason for this difference could be the significantly bigger radial growth at the mid height of the SR trees in the 3rd and 5th years after thinning. The relatively short 5-year period of influence of the strip road on the shape of the trunk did not cause any other discernible differences in reference to the ST trees. Pines are described as reacting in a similar way [Stemp- 72 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski ski et al. 2011]. In that particular research, an insignificantly greater ovality was observed adjacent to the strip road in the 7 years following its creation. Ovality Within the research, no difference in ovality was found between the trees from either of the analysed locations. In both the SR and ST trees, ovality was very small and the trunks maintained a shape resembling a circle [table 4]. A round trunk cross-section is typical for commercial softwoods grown under natural conditions where an equally small (4%) trunk defect has been diagnosed [Tong, Zhang 2008]. A lack of defects in the incremental growth rings around the pith area in comparison to the circumference area was also confirmed by Saint-André and Leban [2000]. They confirmed a clear elliptical shape of growth rings located closer to the circumference of spruce. Therefore, with growing age, an increase in ovality might be expected, which in turn could have a direct effect on the quality of the wood. Table 4. Ovality (mean) at different heights along the stem Tabela 4. Względne spłaszczenie (średnie) na badanych wysokościach Kraft Class Klasa Krafta I Dominant I Górujące II Codominant II Panujące III Intermediate III Współpanujące Trees along strip road (SR) Drzewa przy szlaku (PS) Trees in the stand (ST) Drzewa w drzewostanie (WD) d1.3 d1/2cb dcb d1.3 d1/2cb dcb 0.0435 0.0455 0.0168 0.0312 0.0407 0.0208 0.0257 0.0207 0.0248 0.0307 0.0247 0.0216 0.0344 0.0249 0.0131 0.1325 0.0402 0.0053 d1.3 – breast height; d1.3 – pierśnica d1/2cb – halfway up the pruned trunk; pll – połowa oczyszczonej strzały dcb – crown base; dcb – podstawa korony The number of trees exposed to the risk of increased ovality could be reduced by an increased distance between the strip roads. Increasing this distance to a certain degree does not exclude the use of harvesters [Mederski 2006, Modig et al. 2012]. However, as Bembenek et al. [2013b] observed, there might be a situation where mechanical damage occurs as a result of pulling trees from inter-strip road areas. This could also result in the creation of different structural defects (e.g. ingrown bark, scars) which are characteristic of spruce stands exposed to low level mechanised forest operations [Michalec et al. 2013]. For this reason, it would seem purely academic to omit scars under PN-EN 1927-1 standards. This is a defect present on trees adjacent to the strip road which could equally have been Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst) 73 caused by logging [Karaszewski et al. 2013a; 2013b] as well as by grazing and stripping. This situation is even more applicable to spruces which are commonly attacked by tree rot following stripping. Consequently, this leads to a depreciation in the quality and value of the timber. Conclusions The assumed hypothesis, which stated that greater access to sunlight through the creation of strip roads would create defects in the shape and structure of spruce trees was not confirmed (at least not statistically). One explanation for the obtained results is the relatively short period examined in the research. However, some trend was noted, namely a more intensive increment appearing in the last, fifth year of observation (SR d1/2cb) (fig. 1). Besides the described delay in the growth reaction after the thinning took place, it will probably take time until the trees build up bigger crowns to cover new areas of light, and these asymmetric crowns may finally lead to pith eccentricity and ovality. In the 5 years following the creation of the strip road within the 34-year-old stand, no significant differences in pith eccentricity, taper and ovality were observed. The size of these defects was lower than their permitted levels for class A round timber under PN-EN 1927-1 [2008]. Insignificant changes in stump morphology support the validity of strip roads in second age class stands. Nevertheless, a tendency for the SR trees to have increased incremental growth, particularly in the middle of the trunk, as well as an increase in the taper of mid tree logs from the SR trees was observed. For this reason, it is crucial to continue research into this area, particularly since the described defects have been addressed and have limits placed on them under EU laws concerning the wood in circulation in Europe. References Akachuku A.E., Abolarin D.A. [1989]: Variations in pith eccentricity and ring width in teak (Tectona grandis L. F.). Trees [3]: 111–116 Anonymous [2012]: R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0. 7, 6 Bembenek M., Mederski P.S., Erler J., Giefing D.F. [2011]: Results of large-size timber extracting with a grapple skidder. Acta Sci. Pol., Silv. Colendar. Rat. Ind. Lignar. 10 [3]: 5–14 Bembenek M., Giefing D.F., Karaszewski Z., Mederski P.S., Szczepańska-Álvarez A. 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Wood Science and Technology 29: 451–465 List of standards EN 1310:1997 [1997]: Round and sawn timber – Method of measurement of features PN-EN 1927-1 [2008]: Qualitative classification of softwood round timber – Part 1: Spruces and firs WPŁYW SZLAKÓW OPERACYJNYCH NA WYBRANE WADY DREWNA ŚWIERKA POSPOLITEGO (PICEA ABIES (L.) H. KRAST) Streszczenie Zakładanie szlaków operacyjnych staje się niezbędne przy stosowaniu współczesnych technologii w gospodarce leśnej. Ich obecność to również zwiększony dostęp do światła dla drzew rosnących na ich skraju, co z kolei może wpływać na różnice we wzroście tych drzew w porównaniu z drzewami wewnątrz drzewostanu. Celem pracy była analiza częstości występowania niektórych wad budowy i kształtu mogących wpływać na jakość surowca drzewnego w 5 lat po wykonaniu zabiegu. Drzewostan świerkowy w wieku 34 lat został poddany trzebieży schematycznej poprzez wycięcie co 8. rzędu drzew. Analizie poddano drzewa rosnące przy szlaku PS (z asymetrycznie większymi stoiskami i dostępem do światła) oraz drzewa wewnątrz drzewostanu ( WD 5–10 m od osi szlaku). Badano przyrosty na wysokości pierśnicy, w połowie długości między pierśnicą a podstawą korony i u podstawy korony oraz obliczono przeciętny przyrost, mimośrodowość rdzenia i zbieżystość. Nie zaobserwowano występowania statystycznie istotnych różnic pomiędzy analizowanymi cechami drzew PS i WD, jednakże u drzew rosnących PS zaobserwowano istotnie większą zbieżystość kłód środkowych w porównaniu z odziomkowymi. W krótkim okresie (5 lat) po założeniu szlaków w drzewostanie świerkowym II klasy wieku nie stwierdzono zatem statystycznie istotnych różnic w morfologii pni drzew rosnących przy szlaku i w drzewostanie. Niemniej jednak zaobserwowano: 1) tendencje do zwiększonych przyrostów u drzew PS (szczególnie w połowie pnia) w 5. roku po wykonaniu zabiegu oraz 2) wzrost zbieżystości kłód środkowych wyrobionych z drzew PS. Wyniki te sugeru- 76 Mariusz Bembenek, Dieter F. Giefing, Zbigniew Karaszewski, Agnieszka Łacka, Piotr S. Mederski ją przeprowadzenie podobnych badań w dłuższym odstępie czasowym (niż 5-letni) od założenia szlaków. Słowa kluczowe: jakość drewna, trzebieże, szlak operacyjny, wady drewna, świerk pospolity (Picea abies (L.) H. Karst) Acknowledgements The authors would like to thank Jaroslaw Fahl and Jacek Bobek for their help with the field research. Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.031.06 Agnieszka Jankowska, Paweł Kozakiewicz6 THE IDENTIFICATION OF CHARCOAL FROM ARCHAEOLOGICAL FINDS IN RISAN (MONTENEGRO) The research aimed to identify two sets of charcoal found in a Hellenistic house in Risan (Montenegro) on the Kotor Gulf. The finds date from the 3rd century BC. The study included macroscopic and microscopic observations. Based on macroscopic observation and taking into account the habitat requirements and the range of particular species near Risan and the Kotor Gulf, the first set of charcoal found near a ceramic vessel was attributed to fir wood (Abies sp.), while the charcoal found in the room “with the treasure” was attributed to oak wood (Quercus sp.). The study has added to the body of evidence in favor of the effective botanical identification of charcoal from archeological finds. Keywords: Risan, archaeological excavation, wooden charcoal, identification of charcoal Introduction The remains of wood from archaeological excavations usually fall into two types of findings. The first type is uncharred wood with a high natural durability, such as oak, ash, elm, pine, larch, and probably yew, alder and spruce. The second type of findings is the charred wood of the species listed above and wood species with a low natural durability, but which could survive in the form of charcoal [Dzbeński 1977; Dzbeński, Kozakiewicz 2002]. Wood charcoal forms as a result of the slow pyrolysis of wood when burned in an inadequate supply of oxygen [Asouti 2006]. Identifying charred wood involves technical difficulties but identification is usually possible because the anatomical features of the wood remain intact during the carbonization process [Smart, Hoffman 1989; Prior, Gasson 1993]. Thus identification of wood charcoal can be made at family or genus level. But due to the very similar cellular morphology of the taxa within the same genus, making Agnieszka Jankowska, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] Paweł Kozakiewicz, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] 78 Agnieszka Jankowska, Paweł Kozakiewicz species-level identification is usually impossible [Tennessen et al. 2002]. The ideal method for identification requires microscopic observation by transmitted light [Koeppen 1972]. Charcoal has reflective surfaces, which means that a standard microscope using direct light sources generally creates too much contrast to view the cells. A metallurgical microscope, with a light source that is transmitted directly down onto the sample through the objectives, and then retransmitted from the sample back through the objectives, eliminates reflection. Charred wood retains its original structure, but preparing microscope preparations are severely hampered due to the significant friability. This is why only the external structural features visible in reflected light on fracture can be taken into account at the identification stage [Hawes, Graham 2009]. A charcoal reference collection is relatively simple to prepare. The first step is to accumulate a collection of wood of known identity and then convert it to charcoal. Wood specimens should be large enough so that after charcoaling they can be split and broken to show the sharp structural details of the cross, radial, and tangential surfaces. In exceptional cases, for example quite charred fragments of wood, after using the technique of embedding the samples of wood in binders to consolidate the weakened tissue, making microscopic preparations is posible. The observation of microscopic preparations in transmitted light often reveals details of the internal structure of the material, allowing accurate identification [Dzbeński, Umgelter 1974]. Despite the significant degree of difficulty of the work, identification of charred wood is possible. This is confirmed by numerous reports, such as the identification of samples of charred wood from excavations in Krzemionki, Grodzisk and Izdbeki, Krzesk, Haćki, Krosno [Dzbeński, Kraińska 1985, 1986, 1991, 1992], Grodziszcz Mazowiecki [Kozakiewicz, Dzbeński 1997], Lovosice in the Czech Republic [Petrlíková, Beneš 2008], Yenibademli Mound in western Turkey [Yaman 2010], Oiartzun in the Basque Country [Moreno-Larrazabal et al. 2011] and Novae in northern Bulgaria [Jankowska, Kozakiewicz 2011]. Material and method The study was conducted on two sets of charcoal found in June 2011. This material came from the old town of Risamium (Rhizon, present-day Risan in Montenegro), situated on the Kotor Gulf, on the Adriatic coast. Archaeological excavations in Risan have been conducted by the Centre for Research on Antiques from South-Eastern Europe, Warsaw University, since 2000. During excavations carried out in a Hellenistic house, a ceramic dish filled with coins was discovered under the floor of one of the rooms. The very clear archaeological layout allowed researchers to conclude that the vessel was covered with rubble, in the form of charcoal, after a fire. Charcoal was found in two layers – one layer lying below (probably material from the first set) and the other layer The identification of charcoal from archaeological finds in Risan (Montenegro) 79 lying above or in the floor of the room (probably material from the second set). The hidden ceramic dish dates from 229 BC. The first set of charcoal was found at a depth of 1.06 m with the ceramic vessel. The charcoal was in the form of several small pieces in the shape of cubes with side lengths equal to approximately 15 mm. The second part of the material was found at a depth of 0.87 m, described as material found in the room “with the treasure”. The material was in the form of small pieces similar to the shape of a cube. The length of the largest piece was approx. 35 mm. The scope of the study included macroscopic and microscopic observations. On the basis of literature data concerning the range and the occurrence of selected tree species in Europe, the supporting analysis predicted the likelihood of a type of wood used in Risan in the 3rd century BC. Results and discussion Identification of charcoal found near a ceramic vessel The visible macroscopic features supported the conclusion that all the pieces of charcoal came from coniferous wood. In the charcoal elements, there was a lack of items such as vessels or the grouping of parenchyma cells, which may indicate another type of wood. However, the tracheids indicated coniferous wood - elements forming the structure of the material (fig. 1). a) b) Fig. 1. Charcoal – a) 20x, b) 200x Rys. 1. Węgiel drzewny – a) powiększenie 20x, b) powiększenie 200x The earlywood created made from thin walls and high diameter tracheids. The closer to the end of annual growth, the smaller the diameter of the tracheids 80 Agnieszka Jankowska, Paweł Kozakiewicz and the thicker the walls of the tracheids. In latewood, the tracheids flattened in the radial direction. No resin conductors on the cross-sectional and longitudinal crosssections were observed. The transition from earlywood to latewood was soft. Among the timber species from the temperate zone this set of features is characterized by only fir Abies. Many species of the kind Abies are known in Europe: A. alba Mill., A. cephalonica Loud., A. cilicica Carr., A. nebrodensis. Given the habitat requirements and range of particular species, it can be said that the wood stored in the form of charcoal found in Risan may have come from the tree of the genus Abies cephalonica Loud. – Greek fir. Based on the microscopic observation of charcoal in reflected light the species could not be determined and thus wood of the fir Abies alba Mill. [Kapa 2010] could not be excluded. Identification of wood found in the room „with the treasure” Visible macroscopic features allowed the conclusion to be drawn that all the pieces of charcoal were formed from oak wood (Quercus sp.). The identification of oak was certain as clear distinctive features could be observed even in the charred fragments (fig. 2). This was ring-porous wood with tight rings of large vessels in the earlywood. The vessels in the earlywood with large diameters (from 0.1 to 0.4 mm) were clearly visible to the naked eye. The small vessels in the latewood formed characteristic, radially extending, aggregations often looking like flames of fire. Wide wood rays were clearly visible in all three anatomical sections. Fig. 2. Charcoal (magnification 20x) Rys. 2. Węgiel drzewny (powiększenie 20x) Among the timber species from the temperate zone this set of features is characterized by only oak. However, even taking into account the microscopic methods, secondary and tertiary recognizable features did not enable the distin- The identification of charcoal from archaeological finds in Risan (Montenegro) 81 guishing of different species of oak among the oak trees growing in Europe. The most widely occurring in Europe is the European oak (Quercus robur L. and Quercus petraea Liebl.) and other oak species (Q. pubescens Wild., Q. cerris L., Q. ilex L., Q. suber L.). Given the habitat requirements and ranges, it could be concluded with a high probability that the wood charcoal found in Risan could be from wood of a species of European oak (Quercus robur L.) [Kapa 2010]. Conclusions The study confirms that the identification of charcoal is possible due to the good state of preservation of the structural elements of the wood, particularly the woody parts (vessels, tracheids, fibers). Botanical identification was limited by the possibility of only observing the primary and secondary structural features, referring to the relevant species of wood. Due to the considerable fragility of the material making microscopic preparations is not possible. Identification was limited to observation of the material in reflected light. Based on the results of microscopic analysis and taking into account the habitat requirements and the range of particular species, it was found that: 1. The charcoal found near the ceramic vessel was attributed to fir wood (Abies sp.). 2. The charcoal found in the room “with the treasure” was attributed to oak wood (Quercus sp.). References Asouti E. [2006]: Factors affecting the formation of an archaeological wood charcoal assemblage. http://pcwww.liv.ac.uk/~easouti/methodology_application.htm Dzbeński W. [1977]: Oznaczanie składu gatunkowego węgli drzewnych z wykopalisk w Radzikowie (gm. Czerwińsk, woj. płockie) [dla Instytutu Historii Kultury Materialnej PAN] Dzbeński W., Krasińska H. [1985]: Ekspertyza składu gatunkowego węgli drzewnych z wykopalisk archeologicznych w Mierzanowicach i Wojciechowicach (woj. tarnobrzeskie) oraz Krzemionkach (woj. kieleckie). Warszawa [dla Państwowego Muzeum Archeologicznego w Warszawie] Dzbeński W., Kozakiewicz P. [2002]: Untersuchung von verkohltem Ausgrabungsholz aus flachgelegenen Kulturschichten. Folia Forestalia Polonica Seria B Drzewnictwo [33]: 15–23 Dzbeński W., Kraińska H. [1986]: Ekspertyza składu gatunkowego węgli drzewnych z wykopalisk archeologicznych w Grodzisku i Izdebkach (woj. siedleckie). Warszawa [dla Instytutu Archeologii Uniwersytetu Warszawskiego] Dzbeński W., Kraińska H. [1991]: Ekspertyza składu gatunkowego węgli drzewnych z wykopalisk archeologicznych w Haćkach, woj. białostockie (II etap badań identyfikacyjnych). Warszawa [dla Wojewódzkiego Konserwatora Zabytków w Białymstoku i urzędu Gminy w Bielsku Podlaskim] 82 Agnieszka Jankowska, Paweł Kozakiewicz Dzbeński W., Kraińska H. [1992]: Ekspertyza w zakresie identyfikacji botanicznej i składu gatunkowego węgli drzewnych z palenisk w Krośnie (gm. Pasłęk, woj. elbląskie). Warszawa [dla Instytutu Archeologii Uniwersytetu Warszawskiego] Dzbeński W., Umgelter A. [1974]: Orzeczenie w sprawie zwęglonego drewna pochodzącego z wykopalisk w Worytach pow. Olsztyn (II etap badań). Warszawa [dla Instytutu Historii Kultury Materialnej PAN w Warszawie] Hawes K.L., Graham T. [2009]: Woodchip Analysis from TU4. Journal of Wetland Archaeology 9: 127–134. University of Exeter, UK Jankowska A., Kozakiewicz P. [2011]: Identyfikacja węgli drzewnych i odcisku drewna w opus caementitium z Novae (Moesia Inferior). Novensia 22: s. 119–126 Kapa M. [2010]: Introductory Report on Nature Conservation in Montenegro – Podgorica, October 14, 2010. [Document prepared for Bern Convention the Ministry for Spatial Planning and Environment of Montenegro] Kozakiewicz P., Dzbeński W. [1997]: Badanie struktury wykopaliskowych węgli drzewnych metodami mikroskopii elektronowej i spektrofotometrii. Materiały Konferencji „Analityka chemiczna w badaniach środowiska naturalnego”. Warszawa, September 15th–16th 1997: 61–68 Koeppen R.C. [1972]: Charcoal identification. U.S. Forest Service Research Note FPL-0217 Moreno-Larrazabal A., Urteaga M., Zapata L. [2011]: Identification of archaeological wood remains from the roman mine of Arditurri 3 (Oiartzun, Basque Country). Archaeological charcoal: natural or human impact on the vegetation. SAGVNTVM Extra – 11 – Materials from 5th International meeting of charcoal analysis “Charcoal as cultural and biological heritage” Valencia, September 5th–9th 2011: 159–160 Petrlíková V., Beneš J. [2008]: Anthracological analysis of charcoal fragments from the La Tène, a Roman and the Early Medieval settlement area in Lovosice and from the Roman period production centre in Kyjice, Archeologické rozhledy 60: 93–113 Prior J., Gasson P. [1993]: Anatomical changes on charring six African hardwoods. IAWA Journal 14 [1]: 77–86 Smart T.L., Hoffman E.S. [1989]: Environmental Interpretation of Archaeological Charcoal [in]: Hastorf C. A., Popper V. S. Current Paleoethnobotany – Analytical methods and cultural interpretations of archaeological plant remains, Chicago Tennessen, D., Blanchette R.B., Windes T.C. [2002]: Differentiating aspen and cottonwood in prehistoric wood from Chacoan great house ruins. Journal of Archaeological Science 29: 521–527 Yaman B. [2010]: Anatomy of archaeological wood charcoals from Yenibademli Mound (imbros), western Turkey. Mediterranean Archaeology and Archaeometry 11 [1]: 33–39 The identification of charcoal from archaeological finds in Risan (Montenegro) 83 IDENTYFIKACJA WĘGLI DRZEWNYCH ZE STANOWISKA ARCHEOLOGICZNEGO W RISAN W CZARNOGÓRZE Summary Przeprowadzone badania potwierdzają możliwość identyfikacji gatunkowej węgli drzewnych. Trudności wiążące się z identyfikacją wynikają z ograniczenia obserwacji analizowanego materiału w postaci preparatów mikroskopowych w świetle przechodzącym. W niniejszym artykule zaprezentowano wyniki identyfikacji gatunkowej dwóch zbiorów węgli drzewnych znalezionych na obszarze domu hellenistycznego w Risan w Czarnogórze. Znaleziska są datowane na trzeci wiek p.n.e. Zakres badań obejmował obserwacje makroskopowe i mikroskopowe. Na podstawie wykonanych obserwacji i po uwzględnieniu doniesień literaturowych z zakresu wymagań i występowania poszczególnych gatunków drzew w okolicach Risan nad Zatoką Kotorską stwierdzono, że węgle należące do pierwszego zbioru (rys. 1), znalezione przy ceramicznym naczyniu wypełnionym monetami, pochodzą z drewna jodły. Drugi zbiór węgli (rys. 2), znaleziony w pomieszczeniu „ze skarbem”, to pozostałości drewna dębowego. Słowa kluczowe: Risan, znaleziska archeologiczne, węgle drzewne, identyfikacja węgli drzewnych. Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.037.07 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć 7 WOOD BIOMASS FROM PLANTATIONS OF FAST-GROWING TREES AS AN ALTERNATIVE SOURCE OF WOOD RAW MATERIAL IN POLAND The article presents the results of research on the sources and potential of plantations of fast-growing trees in Poland, as well as the advantages and difficulties connected with them. Additionally, the paper describes the suitability of wood biomass from plantations of fast-growing trees for production and energy purposes. Moreover, the article oulines difficulties in the interpretation of such terms as “fast-growing trees”, “plantation crops”, and “plantation” in the context of place and activities connected with the procurement of biomass from outside forest ecosystems. Keywords: fast-growing trees, plantation crops, wood biomass, survey Introduction Wood is a natural raw material, which is ecological at every stage of its use for material purposes. At the same time, it is one of the oldest carriers of renewable energy. This dualism characteristic of wood biomass, including biomass originating from fast-growing trees, defines the areas and lines of its possible use. Simultaneously, it poses dilemmas connected with the rationality of alternative applications of wood, i.e. its use for production purposes (for material processing) or energy purposes. This issue has currently become more important not only in Poland, but also on a global scale, as the management of wood biomass as an energy carrier is connected with the need to prevent adverse climate change Aleksandra Szostak, Wood Technology Institute, Poznan, Poland e-mail: [email protected] Gabriela Bidzińska, Wood Technology Institute, Poznan, Poland e-mail: [email protected] Ewa Ratajczak, Wood Technology Institute, Poznan, Poland e-mail: [email protected] Magdalena Herbeć, Wood Technology Institute, Poznan, Poland e-mail: [email protected] 86 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć resulting from the greenhouse effect, the indispensability of both the reduction of green house gas emissions, including mainly CO2, and an increase in energy safety and the diversification of the available energy sources. Presently, there are in Poland few possibilities of consuming energy from renewable sources other than wood biomass (wind power, solar radiation, geothermal sources, aerothermal and hydrothermal energy, non-wood biomass, hydropower or the power of waves, currents and sea tides)1. The generation of energy from biomass, including biomass from fast-growing trees, is considered to be the fastest way for Poland to fulfil its international commitments concerning the production of electric energy and heat from renewable sources (the share of energy from renewable sources in terms of the gross consumption of final energy at a level of 15% by 2020 and 20% by 2030). In 2010, biomass carriers accounted for 85% of the production of renewable energy at a level of 6.9 Mtoe (tonne of oil equivalent). According to specialists, those carriers were dominated by wood biomass2 within which the share of biomass from fast-growing trees was small and hard to unambiguously define. Since recent years have witnessed deficits in raw wood material intended for material purposes, and a growing competition for wood demonstrated by the power sector (where, at the same time, relatively large forest areas are protected due to the environmental functions they fulfil), the optimum use of available and potential resources of various wood biomass types, and thus the alternative resource of biomass from fast-growing trees, is an important issue in the wood biomass market. It should be stressed that despite the fact that the problem of the procurement of biomass from fast-growing trees is not a new phenomenon in the wood market, it was not until recently that this problem became a point of broad discussion and interest observed in business practice [Mroziński 2009; Rykowski 2009; Pudełko, Faber 2010; Sidor 2011; Faber 2012; Sawicki 2012]. Research methodology The management of plantation crops of fast-growing trees and their development is of great importance, not only for economizing on forest raw wood material and The National Action Plan on Energy from Renewable Sources (adopted by the Council of Ministers in 2010 and amended in 2011) envisages that the set goals regarding use of energy from renewable sources will be achieved mainly by an increase in the production of electric energy from wind power and an increase in the energy use of biomass [Ustawa o odnawialnych źródłach energii 2012]. 2 In the consumption of solid biomass, the share of wood biomass is estimated to be 60% in public and industrial power plants, and 80% of individual consumption [Flakowicz 2011]. 1 Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 87 increasing the diversification of energy sources, but, due to its specificity (most often plantation crops are managed in the form of small and medium-size companies located close to the customer and using local resources), it has the possibility to dynamise economic and social development at a local level. These crops may and should be treated as a new area of agricultural production, an additional source of revenue and effective use of fallow land. Despite these aspects, the market in wood biomass from fast-growing trees is still barely recognized. In light of the above, it is important to begin research aimed at broadening knowledge of this market operation andof the opportunities and possible barriers to its development, especially when the rational management of available raw wood material resources is required and the fast growth of the potential of renewable energy sources is necessary [Szostak et al. 2012]. The aim of the research was to carry out a multifaceted analysis of the market in biomass from fast-growing trees in Poland, including mainly biomass intended for energy purposes. The survey encompassed the main players in the market of biomass from plantation crops of fast-growing trees in Poland, i.e. agriculture, forestry, and the power sector. The survey basically covered the period 2010–2011. Desk research was supplemented with a direct survey, encompassing suppliers and consumers of wood biomass from fast-growing trees, as well as public administration units as an additional possible source of information on the analysed issue. The survey was sent to 194 respondents, of whom: 145 were planters of fast-growing trees, 32 public power plants, and 17 public administration units. 47 respondents answered the survey. Those answers were further analysed. The respondents were dominated by planters of fast-growing trees (64%). Public administration units accounted for 19% of the total number of surveyed respondents, whereas power plants accounted for 17% [Szostak et al. 2012]. Biomass from fast-growing trees – a systematization of basic terms In subject literature, there is a considerable degree of ambiguity as regards the terms used, and often unclear criteria for the classification of biomass from outside forest ecosystems. This concerns the very concept of “fast-growing trees”, but such interpretation issues are also encountered as regards the terms “plantation crops” and “plantation”, which relate to the place and entirety of the activities, understood sensu lato, connected with the procurement of wood biomass from fast-growing trees. By fast-growing trees one means species which facilitate the procurement of raw wood material for the production of wood materials and/or wood intended for energy generation in shortened production cycles, i.e. cycles shorter than traditionally employed in forest management. These tree species are cha- 88 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć racterized by a faster, than in the case of other species, increment in wood mass at a young age3. Wood biomass from outside forest ecosystems, thus from fast-growing trees, may originate from plantations4 or plantation crops5. More and more often these terms are used interchangeably. For centuries, plantations meant so-called forest crops (man-made plantations), most often monocultures [Zawiłkowski 2011]. These plantations are „man-made” and they are subjected to very intensive tending and agrotechnical procedures [Rykowski 2009]. In the case of fast-growing trees, plantations are often also called “forest plantations” as opposed to traditional forestry based on natural forests and the harvesting of wood from old-growth forests. In subject literature, one universal definition of plantation or forest plantation has been developed. This concept often means various types of plantations, and in the case of forest species of fast-growing trees, they can even be mistaken for forest. In Poland, in accordance with the Act on Forests [Ustawa o lasach 1991], forests (due to their production, ecological and social functions, choice of grown plants and the intensity of tending procedures) are distinguished from plantations by the commitment of their owners to managing these forests sustainably, maintaining them and assuring their continuous and rational use, guaranteeing the optimum fulfilment of all forest functions at a local, national and global level without damage to other ecosystems. According to the Food and Agriculture Organisation of the United Nations (FAO), a forest plantation is “an area afforested, mainly for profit, with fast growing tree species, which, thanks to intensive growing, is characterized by high and sustainable wood production and also the high quality of the harvested product tailored to market requirements” [Terms and Definitions 2004; Zwoliński 2009]. The FAO considers forest plantations to be one of the forms of forest, classified (together with semi-natural forests, i.e. forests composed of indigenous tree species established by planting or seeding with a share of naturally restored trees) as so-called planted forests created through planting, dedicated seeding or the sowing of shoots of planted trees both indigenous and introduced [Zajączkowski 2009]. In Polish economic practice, the FAO’s definition of (forest) productive plantations, which are established mainly with the view of wood production for In Polish forestry, these are trees, which in comparable habitats in lower age classes (25–40 years are characterized by better production effects than pine, which dominates in Poland [Zajączkowski 2009]. 4 A large area used for a many-year cultivation of a single type of plant [Encyklopedia 1998]. 5 Irrespective of whether it concerns forests or arable land, it means the entirety of procedures with the view of creating the optimum conditions for plants to grow and increasing the culture of their growth [Encyklopedia 1998]. 3 Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 89 industrial purposes, is the closest to the concept of plantations of fast-growing trees6. In Poland, it is recognized that the production of wood in shortened production cycles is possible in the case of “the intensive cultivation of clones7 or narrow populations of trees, which, depending on the origin of the planting material used, are called plantations or plantation crops of fast-growing trees” [Mroziński 2009], whereas: –– in the case of plantations of fast-growing trees, narrow genetically homogeneous populations, families or clones of fast-growing trees are used, which are selected in terms of their increment and/or quality characteristics (sometimes this term is limited to vegetatively reproduced cultivated tree varieties, mainly poplars) [Zajączkowski, Załęski 2007], –– plantation crops of fast-growing trees are established mainly using generative progeny (from seeds) of chosen populations [Zajączkowski, Załęski 2007]. The method of establishing and managing plantation crops of fast-growing trees, the length of a production cycle or the planting material used, depend mainly on the goal of the plantation and the purpose for which the biomass obtained from the trees is intended [Bodył 2010]. In public statistics, the area of plantations of fast-growing trees and shrubs on farms is defined based on current agricultural research8 and data from General Agricultural Registrations9, including plantations for energy purposes, managed on both forest lands and arable lands. The term “fast-growing trees and shrubs” means “specialist crops of ligneous plants characterized by an early culmination of increment (e.g. larch, spruce, birch, willow, aspen, and selected varieties of poplar) with the view of gaining in the short term (15 years or less) predetermined economic results, such as a high efficiency of raw wood material, seeds, fruits or Christmas trees”. The above deliberations concerning biomass from fast-growing trees demonstrate the large degree of arbitrariness and ambiguity as regards the interpretation In the case of forest plantations, the FAO differentiates between two kinds depending on their function: productive plantations, i.e. dedicated to the production of wood for industrial purposes („[…] stands of introduced species and stands of native species, established through planting or seeding mainly for the production of wood […]”), and protective plantations, i.e. established in order to bring environmental benefits [Zajączkowski 2009]. 7 Vegetative progeny of well-studied trees of even-growth features [Zasady hodowli lasu 2012]. 8 This is research on farms and other entities which use arable lands. The research is carried out annually based on report R-05, i.e. Report on land use, crop area and harvest (it encompasses entities which use arable land of more than 1 ha), and representative survey R-CzSR of land use, crop area, livestock (carried out on a sample of 3% of individual farms which had been drawn). 9 Last General Agricultural Registration was in 2010. 6 90 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć of terms used in connection with this issue, and at the same time they show the urgent need for the standardization of the terminology used in legal regulations and in business practice. Additionally, the above analysis has led to the identification of common elements in the definitions “plantation” and “plantation crops of fast-growing trees”, i.e.: –– they are both cultivations of trees established with the view of obtaining a larger supply of wood biomass of a required quality in a relatively short period, –– their permanent feature is their “artificial origin” from adequately-selected or genetically-modified tree species, –– they are managed in the form of regular spacing and require tending and agrotechnical procedures. Taking the above into consideration, this article basically uses the term “plantation crops of fast-growing trees”, and sometimes the term “plantations of fast-growing trees” (in Poland, mainly in the case of poplar plantations). The potential of crops of fast-growing trees Within the Polish economy, wood biomass from fast-growing trees is produced in two sectors, i.e. agriculture and forestry. It is characteristic that these sectors differ significantly in terms of the establishment and management of plantation crops of fast-growing trees. This especially concerns the running time of such an operation, its goals, and also its form. In Poland, activities connected with the establishment and management of plantation crops of fast-growing trees in agriculture were engaged in relatively recently, when in the 1990s an increased interest in the use of natural energy sources was observed. These activities gathered pace after Poland’s accession to the European Union, when the EU rules concerning energy generation from renewable sources were adopted. Agriculture became the sector in which wood biomass from fast-growing trees is produced intentionally, in an organized way, and based on specialist agrotechnology, mainly with the view of increasing its potential for energy generation. The players in the market involved with this kind of wood biomass are farmers and farm producers, as well as companies registered with the Agricultural Market Agency purchasing and processing biomass. The production and harvesting of biomass from fast growing trees for energy purposes has become a new line of agricultural production, which is often defined as the agro power industry. In connection with this activity, the term “power agriculture” appears alongside the traditional term “food agriculture” [Budny 2005; Tworkowski, Szczukowski 2005]. The potential of plantation crops of fast-growing trees in agriculture mainly depends on the availability of lands (which are primarily used for food production), climate conditions, and water supply. An important factor affecting the popularization of the production of biomass from fast-growing trees is the in- Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 91 flow of financial capital. This was confirmed by the fact that interest in biomass production observed in Polish agriculture, especially in the period 2005–2008, was brought about by economic factors, i.e. the craving to increase one’s income through gaining subsidies – initially from the national budget and later on mainly from external financial sources in the form of EU funds. It is worth noting that, in the opinion of specialists, the development of high-energy crops, including crops of fast-growing trees, is an example of the implementation of innovative practices, which take into account environmental protection, and it is conducive to the economic activation of rural areas, which is especially important [Chodkowska-Miszczuk, Szymańska 2011]. In Polish forestry, plantation crops of fast-growing trees are managed on arable lands and in forests. Furthermore, it may be assessed that the plantation crops are both general and dedicated. According to information from the Central Statistical Office of Poland, the area of plantations of fast-growing trees on farms exceeds 143 thou. hectares, of which plantations on arable lands cover an area of approximately 8 thou. hectares, and in forests more than 135 thou. hectares (2010). In these areas, dedicated plantation crops of fast-growing trees are also managed with the view of harvesting the wood biomass for energy purposes. In the period 2010–2011, the total area of dedicated plantation crops of fast-growing trees covered 11.2 thou. hectares, of which crops on arable lands covered approximately 6.2 thou. hectares (i.e. 55%), and in forests approximately 5.0 thou. hectares (45%) – table 1. Table 1. The area of plantation crops of fast-growing trees intended for energy purposes in agriculture1 in Poland in the period 2009–2011 Tabela 1. Powierzchnia upraw plantacyjnych drzew szybkorosnących w rolnictwiea do celów energetycznych w Polsce w latach 2009–2011 ha 2009 2010 2011 b c Area of plantation crops Province Województwo Powierzchnia upraw plantacyjnych on arable on arable lands lands in forests in total on arable lands in total na użytkach rolnych 1 Dolnośląskie 2 600.7 3 435.1 4 317.2 5 752.3 6 406.2 7 124.3 8 530.5 Kujawsko-Pomorskie 198.5 161.3 242.6 403.9 181.0 0.4 181.4 Lubelskie 310.7 263.6 260.5 524.1 282.4 118.0 400.4 Lubuskie 410.5 278.7 574.2 852.9 875.7 643.1 1518.8 Łódzkie 214.2 183.3 301.2 484.5 61.7 2.5 64.2 w lasach razem na użytkach rolnych in forests na użytkach rolnych w lasach razem 92 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć Table 1. Continued Tabela 1. Ciąg dalszy 1 Małopolskie 2 63.1 3 35.7 4 292.6 5 328.3 6 34.0 7 65.8 8 99.8 Mazowieckie 763.0 163.0 578.9 741.9 229.0 125.0 354.0 Opolskie 230.1 136.9 130.8 267.7 17.8 36.5 54.3 Podkarpackie 696.9 2197.3 330.7 2528.0 1538.3 2165.7 3704.0 Podlaskie 162.2 245.2 127.1 372.3 229.2 0.0 229.2 Pomorskie 885.8 239.0 213.6 452.6 554.1 1160.3 1714.4 Śląskie 259.6 101.2 249.7 350.9 253.8 11.4 265.2 Świętokrzyskie 99.1 95.1 329.5 424.6 93.0 17.5 110.5 Warmińsko-Mazurskie 576.6 871.0 282.5 1153.5 881.6 120.5 1002.1 Wielkopolskie 786.1 329.9 398.5 728.4 209.6 40.3 249.9 Zachodniopomorskie 574.0 427.0 408.5 835.5 279.8 395.3 675.1 6831.1 6163.3 5038.1 11201.4 6127.2 5026.6 11153.8 IN TOTAL OGÓŁEM On arable lands and in forests/Na użytkach rolnych i w lasach State as of June 30, 2010/Stan na 30 czerwca 2010 roku 3 State as of June 30, 2011/Stan na 30 czerwca 2011 roku 1 2 Source/Źródło: Sprawozdanie o użytkowaniu gruntów, powierzchni zasiewów i zbiorach w 2011 r. (R-05) GUS; Powszechny Spis Rolny w 2010 roku [Grzybek 2011]. In Polish agriculture, the spatial diffusion of innovation in the form of the introduction of plantation crops of fast-growing trees is uneven and observed mainly in the northern and western parts of Poland (fig. 1). The Podkarpackie province deserves special attention, for this region had the largest area of plantations of fast-growing trees. In 2010 in the Podkarpackie province, the area of plantations of fast-growing trees was 2.5 thou. ha, and in 2011 3.7 thou. ha, an increase of approximately 1.2 thou. ha, i.e. 47%. Simultaneously, the locations of plantation crops of fast-growing trees changed significantly in the analysed period: crops on arable lands decreased from 2.2 thou. ha to 1.5 thou. ha, i.e. by 30%, whereas crops in forests increased dramatically, from 0.3 thou. ha to 2.2 thou. ha, i.e. more than 6.5 times. Analysing the size of the area of plantation crops of fast-growing trees intended for energy purposes in particular provinces, one should notice that in the period 2010–2011, the size of the area of these crops and the degree of their concentration changed greatly: in 2011, in comparison to 2010, the area of plantations of fast-growing trees decreased in as many as thirteen provinces. Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 93 pomorskie warmińsko-mazurskie zachodniopomorskie podlaskie kujawsko-pomorskie mazowieckie lubuskie wielkopolskie łódzkie lubelskie dolnośląskie opolskie świętokrzyskie śląskie małopolskie podkarpackie up to/do 200 thou. hectares/tys. ha 201–500 thou. hectares/tys. ha 501–1000 thou. hectares/tys. ha >1000 thou. hectares/tys. ha Source/Źródło: Sprawozdanie o użytkowaniu gruntów, powierzchni zasiewów i zbiorach w 2011 r. (R-05), GUS. Fig. 1. The area of plantation crops of fast-growing trees in agriculture (on arable lands and in forests) in 2011 Rys. 1. Powierzchnia upraw plantacyjnych drzew szybkorosnących w rolnictwie (na użytkach rolnych i w lasach) w 2011 roku This phenomenon, to a large degree, was observed in the following provinces: Łódzkie (a decrease of 7.5-times), Opolskie (5-times), Świętokrzyskie (almost 4-times), Małopolskie (over 3-times), and Wielkopolskie (over 3-times). On the other hand, an increase in plantations of fast-growing trees was observed in just three provinces, i.e. in Pomorskie (4-times), Podkarpackie (by 47%), and Lubuskie (by 78%). In these latter three provinces, the area of plantation crops of fast-growing trees increased by 3.1 thou. ha in total, which was 28% in relation to the total area of crops in Poland in 2011. It should also be noted that changes in the size of the area of plantation crops of fast-growing trees in agriculture were significantly greater on arable lands than in forest areas. In 2011, such crops in forest areas increased only in two provinces, i.e. in Podkarpackie (6.5-times) and Pomorskie (over 5-times). As regards arable lands, such changes were observed in seven provinces: the greatest changes were witnessed in Lubuskie (3-times), Śląskie (2.5-times), and Pomorskie (over 2-times). 94 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć Considering the concentration of plantation crops of fast-growing trees in particular provinces, one should observe that in 2010 the areas of such crops exceeding 1 thou. ha were found only in two provinces, i.e. in Podkarpackie (2.5 thou. ha) and Warmińsko-Mazurskie (1.2 thou. ha), while in 2011, this had risen to four provinces, i.e. Podkarpackie (3.7 thou. ha), Pomorskie (1.7 thou. ha), Lubuskie (1.5 thou. ha), and Warmińsko-Mazurskie (1.0 thou. ha). Generally, in 2010, 72% of the total area of plantation crops of fast-growing trees was concentrated in eight provinces (crops exceeding 0.5 thou. ha), while in 2011, 82% of the total area resided in six provinces. The fast-growing trees cultivated in Polish agriculture on arable lands are dominated by willow, accounting for approximately 90% [Budzyński, Bielski 2004; Grzybek 2008; Grzybek 2011]. An analysis of the area of willow crops in the period 2005–2011 indicates that most of the crops of this tree species were cultivated in 2006 and they covered approximately 7.2 thou. ha (table 2), meaning a 21% increase in relation to 2005. Table 2. The area of plantation crops of willow in agriculture (on arable lands) in Poland in the period 2005–2011 Tabela 2. Powierzchnia upraw plantacyjnych wierzby w rolnictwie (na użytkach rolnych) w Polsce w latach 2005–2011 Years Lata 2005 2006 2007 2008 2009 20101 20111 1 1 Area of crops Powierzchnia upraw ha/ha 5960 7192 6480 6700 6160 5550 5515 For the period 2010–2011, the authors’ own calculations assume that the area of plantation crops of willow accounts for 90% of the total area of plantation crops of fast-growing trees on arable lands Lata 2010–2011 obliczenia własne, przy założeniu, że powierzchnia upraw plantacyjnych wierzby stanowi 90% ogólnej powierzchni upraw plantacyjnych drzew szybkorosnących na użytkach rolnych Source/Źródło: [Grzybek 2008; Grzybek, Muzalewski 2010; Grzybek 2011; Szostak et al. 2012] It can be estimated that the increased interest in willow crops resulted from the introduction of subsidies for the establishment of such plantations. At the same time, it should be noted that this interest proved to be short-lived, despite further subsidies in the period 2007–2008 (national as well as EU subsidies). Since 2007, willow crops virtually ceased to develop, and since 2009 there has been a clear downward trend, probably resulting from the fact that, in 2009, subsidies for this kind of activity were withdrawn. In 2011, willow crops reached a level of 5.5 thou. ha, a 23% decrease in such crops in relation to 2006. It is estimated that in Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 95 Poland, willow is grown by 600 planters, most of them in Warmińsko-Mazurskie and Wielkopolskie provinces [Forowicz 2011]. Generally, it should be said that hitherto in Polish agriculture, dedicated plantation crops of fast-growing trees have been managed to a limited extent, although, thanks to these plantations, wood biomass, which is a raw material for the production of both wood materials and energy (thermal and electric), can be produced in an organized way. Moreover, the establishment of these crops seems to be one of the most positive lines of sustainable local development. Dedicated plantation crops of fast-growing trees which are currently managed in Polish agriculture on an area of approximately 11 thou. ha and the biomass harvested from them can hardly be considered an energy carrier source of some significance. Assuming that 20 tonnes of dry wood mass10 can be obtained from 1 ha of plantation, the total area of plantation crops of fast-growing trees in Poland delivers 220 thou. tonnes of wood biomass per annum. For comparison, according to calculations, the consumption of wood biomass by all its customers (public power plants, industrial power plants, and individual customers) amounted to 10.1–11.5 M tonnes in 2010 [Ratajczak et al. 2012]. Experts estimate11 that Polish agriculture has a very large potential for biomass production, including biomass from plantation crops of fast-growing trees. According to various opinions and estimates, the potential in Poland of lands on which plantation crops of energy plants may be established amounts to 1.1–2.0 M ha [Szczukowski, Tworkowski 2005; Pudełko, Faber 2010; Faber 2012]. The potential of lands that may be used for dedicated energy crops for the power industry (where solid biomass is produced, mainly from fast-growing trees) is estimated to be 0.3–0.6 M ha [Bodył 2012]. Experts have calculated that approximately 3.7–6.5 M tonnes of dry biomass could be obtained from such an area. Such an amount of biomass from agriculture could satisfy 33% of the demand for biomass from the 20 largest system power plants [Pudełko, Faber 2010]. It has also been suggested that plantation crops of energy plants could be located in approx. 1600 communes, i.e. 65% of the total number which is 2479 [Pudełko, Faber 2010; GUS 2012]. Generalising, it may be said that if Polish agriculture does not become a producer of biomass to a significantly larger degree (especially of wood biomass from plantation crops of fast-growing trees), Poland may not achieve the set goals for According to different information sources, 4 tonnes, 8 tonnes, 12.5–21.5 tonnes, 15–30 tonnes, 20 tonnes, or 30–40 tonnes of dry wood mass can be obtained from 1 ha of plantation [Leitfaden bioenergie 2000; Mickiewicz 2004; Fechner 2006; Fabisiak te al. 2008; Zawiłkowski 2011]. 11 In Poland, there is 0.42 ha of arable land per capita. In Germany, that index is 50% less, and in the EU it is 0.19 ha. Much of this land area is made up of soil of bad quality, which could be used for crops of energy plants [Nowe szanse dla rolnictwa… 2012; Prezes Polskiej Izby Biomasy…wnp.pl]. 10 96 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć energy generation from renewable sources. Biomass will be a much sought-after energy carrier, if Poland fulfils the resolutions of the Climate Package 3 × 2012. Bearing this in mind, the power sector has recently taken steps to establish, in cooperation with farmers, new areas of dedicated plantation crops of fast-growing trees, especially willow. The goal of the activity is to assure a future supply of biomass for energy sector entities, i.e. adequate amounts of biomass with the appropriate parameters and at a predictable price. In the case of forestry, it is known that plantation crops of fast-growing trees were established at the beginning of 1950s13. In the period 1956–1975, the establishment of 27 thou. ha of forest plantations of fast-growing trees was envisaged, of which only 11 thou. ha was intended for plantations of trees for manufacturing purposes (the rest was intended to have been Christmas tree plantations). On the other hand, the prognosis of 1972 anticipated that within the 20-year period of 1970–1990, forest plantations of fast-growing trees should have been established on an area of at least 100 thou. ha, and by the year 2000, 300 thou. ha [Zajączkowski 2009]. These plans were not executed. By the end of 1989, only 4.2 thou. ha of such plantations had been established, with 1/3 of the area being used for spruce plantations. In Poland in the forest sector, there is a long tradition of activities connected with plantation crops of fast-growing trees, especially poplar; however, for many decades these activities were not widely popularized. A dominant goal of establishing such plantations was the use of wood biomass for material purposes [Zajączkowski 2009]. Currently in forestry, activities related to the establishment and management of plantation crops of fast-growing trees are declining. This is due to the fact that in Polish forests a semi-natural cultivation of the forest, based on a knowledge of the habitats and their potential, has been practised in accordance with the adopted principle of sustainable growth [Kozioł, Matras 2011]. Since the mid-1970s in the forest sector, no plantations intended for the production of wood for both industrial and energy purposes should be established [Zajączkowski 2009]. After 1989, the area of small plantations established in 1970s began to gradually decrease in size and, according to studies14, in 2011 was 2.5 thou. ha15. The name 3×20 stems from three postulates: a reduction in energy consumption by 20%, reduction in greenhouse gas emissions by 20%, and achievement of a 20% share of energy from renewable sources in terms of total energy consumption in the UE by 2020 [Notatka informacyjna… 2008]. 13 On the initiative of the Ministry of Forestry, in December 1952, a conference on poplar plantations was organized, which was attended by a broad group of interested departments and scientists from forestry faculties of universities and from the Forest Research Institute. This conference is considered to have been the starting point for planned plantation crops of poplar coordinated by the state [Zajączkowski 2009]. 14 A survey carried out by the Wood Technology Institute in Poznan [Szostak et al. 2012]. 15 It can be found in secondary literature sources that 4–10 thou. ha of plantation crops 12 Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 97 However, it has been supposed that the forest sector is now prepared to engage in this activity to a wider extent than previously and intend to develop it. An unquestionable asset is the profound knowledge and experience of specialists in forest management and scientists16. Currently, plantation crops of fast-growing trees are located within the area of 13 out of 17 State Forests Regional Directorates (RDLP) – table 3. Analysis of the extent of such plantation crops in particular RDLPs, shows that the greatest areas are within RDLPs in Lublin – over 0.6 thou. ha, Olsztyn – approximately 0.5 thou. ha, and Radom – approximately 0.4 thou. ha, whereas the smallest areas are within RDLPs in Szczecin and Cracow – 0.06 thou. ha in each location. There are 363 plantations in Polish forestry altogether. Most of them are found within the RDLPs in Olsztyn (62), Torun (58), and Gdansk (57), while the fewest are found within the RDLPs in Cracow (1), Szczecin (11), and Katowice (12). An average plantation land area is 6.9 ha. Particular RDLPs differ from one another in terms of the size of the plantation area. As regards the land area, the largest plantations are located within RDLPs in Radom (15.9 ha) and Olsztyn (15.7 ha), and the smallest within RDLPs in Szczecin (0.5 ha) and Zielona Góra (1.1 ha), meaning that the largest plantations exceed more than twice the national average plantation land area, whereas the smallest account for 7–16% of the national average plantation land area. The main tree species grown on forestry plantations are: poplar, larch, birch, spruce, linden, Douglas fir, maple, willow, and sweet cherry17. Presently, forestry plantations of fast-growing trees are, to a large extent, experimental areas, on which long-term research is carried out. Many of these plantations are being converted into economic stands (this mainly concerns old poplar plantations). of fast-growing trees are located on areas of the State Forest National Forest Holding (PGL LP) [Kozioł, Matras 2011; Sawicki 2012]. 16 For 50 years scientists have carried out research on plantation crops of poplar in the natural conditions in Poland. Research has found that an adequate productivity of a plantation, achieved in Southern and Western Europe, can be obtained through the use of appropriate varieties of poplar, the establishment of plantations in appropriate habitats (III–IV class of land) and with appropriate spacing, the appropriate preparation of the soil and the employment of adequate tending and protective procedures. It was recognized that in the natural and economic conditions of Poland the following trees species can possibly be cultivated: cottonwood and balmy poplar, poplar, aspen, willow, European larch, Douglas fir, Norway spruce, common birch, sweet cherry, locust tree [Bodył 2010; Zajączkowski 2009]. 17 Based on a survey carried out by the Wood Technology Institute in Poznan [Szostak et al. 2012] and [Kozioł, Matras, 2011]. 98 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć Table 3. The area of plantation crops in forestry in Poland in 2011 Tabela 3. Powierzchnia upraw plantacyjnych w leśnictwie w Polsce w 2011 roku State Forests Regional Directorates Regionalna Dyrekcja Lasów Państwowych Number of plantations Liczba plantacji Area of plantation crops Powierzchnia upraw plantacyjnych Average area of plantation crops Średnia powierzchnia upraw plantacyjnych ha Białystok 17 110.9 6.5 Gdańsk 57 339.2 6.0 Katowice 12 26.6 2.2 6.1 Kraków 1 6.1 Krosno 10 47.1 4.7 Lublin 62 624.2 10.1 Łódź 44 116.7 2.7 Olsztyn 29 454.3 15.7 Piła – – – Poznań – – – Radom 24 381.4 15.9 Szczecin 11 5.8 0.5 Toruń 58 248.8 4.3 Warszawa 24 124.6 5.2 Wrocław – – – 14 15.7 1.1 363 2501.3 6.9 Szczecinek Zielona Góra IN TOTAL OGÓŁEM Source: State Forests Directorate General in Warsaw – survey carried out by the Wood Technology Institute in Poznan Źródło: Dyrekcja Generalna Lasów Państwowych w Warszawie – badania ankietowe Instytutu Technologii Drewna w Poznaniu In the opinion of the State Forests Directorate General18, Poland currently lacks areas suitable for the establishment of plantation crops of fast-growing trees. The Agricultural Market Agency has also taken no steps to transfer land for that purpose to the State Forests. Furthermore, as a result of changes in forestry management adopted in 1991, virtually no monocultures have been established [Ustawa o lasach 1991]. Taking the above into consideration, no expansion of the area of plantation crops of fast-growing trees in Polish forestry is envisaged in the near future. Nevertheless, it should be noted that in connection with interest in the 18 An opinion expressed in a survey which was part of direct research carried out by the Wood Technology Institute in Poznan [Szostak et al. 2012] and [Sawicki 2012] Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 99 cultivation of fast-growing trees expressed by producers from the wood sector, e.g. with a view to harvesting the wood for the production of chemical wood pulp and paper, the State Forests National Forest Holding (PGL LP) has started co-operation as regards plantation crops of fast-growing trees19. The role of forestry in this co-operation is to indicate which clones of poplar would be most suitable for the pulp and paper industry. The first experimental crop of this tree species was established on the area of Wichrowo Forest Division (RDLP in Olsztyn), where the staff have many years of experience as regards plantations of fast-growing trees. In 2011, the area of dedicated plantation crops in Poland was 13.7 thou. ha in both the agriculture and forestry sectors together. In the opinion of specialists, in 2020 the area of such plantation crops should amount to approximately 0.5 M ha in order to meet the demands of the power sector, i.e. so-called public power plants, for biomass from fast-growing trees [Stefaniak 2009; Forowicz 2011; Rynek biomasy]. Consumers of wood biomass from fast growing trees Over the last few years, due to the increasing demand for wood, wood biomass from plantation crops of fast-growing trees has become one of the alternatives to forest wood sources of raw wood material. Wood from this source can be used for material and energy purposes. The suitability of wood biomass from plantation crops for material and energy purposes stems from both the properties of the biomass and the existing technologies used for material and energy processing. However, it should be stressed that in business practice, wood biomass from plantation crops of fast-growing trees is mainly treated as a source of energy. This was confirmed by a survey carried out amongst planters of fast-growing trees, where 89% of the respondents indicated that wood biomass from plantation crops was used for energy purposes [Szostak et al. 2012]. The wood of fast-growing tree species, mainly willow and poplar, from agricultural and forest plantation crops, can be useful as a substitute for wood particles and fibres obtained from forest wood and used in the production of wood-based panels, and for the production of various dedicated composite materials [Ratajczak et al. 2011]. The form of the alternative raw materials makes it possible to obtain from them particles of various types and geometry, and the diverse specific density creates the possibility of producing composite materials of different structures, density and strength. The wood from agricultural and forest plantation crops 19 In September 2008, the State Forests, International Paper Kwidzyn Sp. z o.o., and the Forest Research Institute signed a trilateral agreement on co-operation in the field of the management of plantation crops of poplar dedicated to the purposes of the pulp and paper industry. This agreement defines the terms and conditions of the 15-year co-operation concerning experiments on Polish and foreign varieties of poplar [Bodył 2011; Sawicki 2012]. 100 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć can also be used in the pulp industry. In general, the recently rising deficit in forest raw material used for the production of wood pulp is the reason for action which is currently being taken with a view to establishing plantations of trees with defined features, which are grown from selected material characterized by the greatest suitability for the needs of a specific consumer/industry [Bodył 2011; Sawicki 2012]. One material use of the wood from fast-growing trees is the production of wood pellets and briquettes. The technology for the manufacture of these products from raw material originating from agricultural and forest plantation crops, makes it possible to obtain products of high quality, smooth and glassy surface, and good calorific value (17–18 MJ/kg) [Kwaśniewski 2008]. Generalising from former knowledge, it should be said that in the wood sector it is mainly wood from forests that has been used for material purposes; however, in the light of the growing demand for this raw material, the procurement of wood biomass from outside forest ecosystems is becoming important. One of the remedies for the lack of balance between the supply of and demand for wood biomass is to increase the production of wood from agricultural and forest plantation crops. The suitability of wood biomass of such origin for the production of agglomerated wood-based panels and wood pulp, which has been confirmed by many studies, simultaneously means the necessity of creating an adequately-sized raw material base [Oniśko 2011]. Bearing this in mind, it is necessary to prepare packets of instruments stimulating and encouraging the intensive establishment of new plantation crops of fast-growing trees and the development of existing ones. At the same time, steps taken in this area will support active forest management. For the time being, wood biomass from plantation crops of fast-growing trees in Poland is used to a rather insignificant degree for material purposes. This was confirmed by the survey carried out amongst planters of fast-growing trees, where only 10% of respondents indicated that producers from the wood sector were consumers of wood biomass from their plantation crops. The wood from agricultural and forest plantation crops is used for energy generation, thus it supplements in Poland the balance of wood biomass on the energy market (mainly it is wood of frutescent willow and poplar). In Poland, producers of thermal and electric energy are the consumers of wood biomass from fast-growing trees intended for energy purposes. The consumers may be both collective and individual. Taking into account the great demand from the power sector for energy carriers, it should be stressed that the sector may consume a considerable quantity wood biomass, including biomass from agricultural and forest plantation crops. Unfortunately, there is still a lack of a mature and comprehensive system for streamlining the production, distribution, and use of such biomass, for only the simultaneous development of all these elements can assure the success of a system of renewable energy source utilisation, which is based on wood biomass from plantation crops. Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 101 According to specialists [Bartczak 2008; Sidor 2011; Guła 2012; Kutrzuba 2012], in the face of a huge demand for energy, supplies of wood biomass from dedicated plantation crops are important for public power plants. At the same time, wood biomass from these sources should be mainly used to generate heat on a local scale, i.e. within no more than 50–70 km from the place of production, determined by transport profitability. The above statements are confirmed, to some degree, by the survey carried out amongst planters of fast-growing trees [Szostak et al. 2012], namely the answers of respondents suggested that wood biomass from plantation crops was primarily consumed by business entities operating up to 50 km from the biomass source. Such information was given by 79% of the respondents. In this group, most of the respondents (42%) indicated that they supplied wood biomass within a distance of up to 30 km. The survey also suggested that wood biomass from plantation crops of fast-growing trees is mainly consumed by collective customers (75% of the answers). Amongst other consumers, there are individual customers (29% of the answers) and middlemen who deliver biomass to power producers (18% of the answers). The indicated group of collective consumers was composed mainly of public power plants (68% of the answers), primarily including combined heat and power plants (32%), municipal/local power plants (11% of the answers), and industrial power plants (11% of the answers). The indicated group of individual consumers was composed mainly of planters, who used such wood biomass to satisfy their own energy demand (29% of the answers)20, and then households, which purchased such biomass to use for heating (7% of the answers). It should be noted that over recent years the interest of power sector entities in wood biomass from agricultural and forest plantation crops has increased considerably. This fact can be considered a drive towards a stabilization of the situation in the currently shallow market in wood biomass used for energy purposes. Some co-operation with farmers as regards the supply of wood biomass from plantation crops has started. Multiannual contracts for the supply of such wood biomass to defined CHP plants and heat-generating plants have been signed. The establishment of a plantation, its tending and harvesting and the transport of the biomass to a given plant has also been agreed. Power sector entities themselves have also established model plantations of fast-growing trees21. In light of the above, it can The establishment and management of plantations of fast-growing trees on small areas can, to a considerable extent, be a solution to the problem of supplying farms with thermal energy. As little as 0.5 ha of willow can provide fuel for a farm for the whole year [Gutowska 2005]. 21 For instance, in industrial areas and on slag heaps owned by Katowice Coal Holding, willow plantations have been established to satisfy the demand from the combined heat and power plant in Tychy [Katowicki Holding Węglowy… 2003]. Large-area plantations of willow are being developed by PGNiG Termika Company, which contracted an area of 350 ha for 17 years for the cultivation of willow [Kozłowska, Kałużna 2012]. The Experimental Station for Grasslands Melioration in Biebrza, as well as local farm20 102 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć therefore be supposed that an individual owner of a small plantation can become a less attractive supplier of wood biomass for a big power company, whose demand for that energy carrier is great. The activity of the power sector consisting in establishment of its own plantation crops of fast-growing trees was confirmed by the survey [Szostak et al. 2012]. The respondents representing power plants (29% of all the respondents) indicated that they used wood biomass from their own plantation crops as well as biomass from plantation crops managed by farmers who had contracts with that particular power plant. The CHP plants surveyed (29% of all the respondents) used wood biomass from their own plantation crops, while heat-generating plants (42%) used wood biomass from their own plantation crops and from plantations located on the lands leased from farmers. All the respondents intended to develop plantation crops of fast- growing trees or at least maintain their previous size, but not one of the respondents planned to liquidate such plantation crops. Secondary sources [Samborski 2011; Chojnacki 2012; Mazurkiewicz 2012; Własne plantacje…] and the survey carried out by the Wood Technology Institute in Poznan [Szostak et al. 2012] suggest that companies from the wood sector are also taking steps to establish their own plantation crops of fast-growing trees for energy purposes. An example is International Paper Kwidzyn Sp. z o.o. – a company which already owns 164 ha of plantations of 3–5 year-old poplar to meet the demand of the company’s own CHP plant. International Paper Kwidzyn has also started the execution of a project (in co-operation with the company Green Word Resources Poland) consisting of the establishment of the biggest plantation of fast-growing poplar in Europe, which is to cover an area of approximately 10 thou. ha over three years and has a target of 25 thou. ha. It is envisaged that the plantation will be established on lands leased from local farmers. To conclude, it should be observed that in comparison to previously small areas of agricultural and forest plantation crops, big plantations established by companies are a prospective source of wood biomass. It should be emphasized that the local availability of biomass as an energy carrier from plantation crops of fast-growing trees is of special importance to its harvesting and the logistics of its supplies, as regular deliveries to customers should be assured. At the same time, it should be noted that the location of power plants in Poland increases the strong competition for biomass resources [Pudełko, Faber 2010], which is especially visible in southern Poland, as 12 (i.e. 63%) out of 19 power plants operate in this area. Therefore, the spatial layout of land for plantation crops of fast-growing trees, is quite uneven and limited in relation to existing consumers of such a type of biomass. ers, manages a plantation of energy willow (approx. 10 ha) to meet demand from the Heat-Power Engineering Company in Grajewo, whereas the demand from the combined heat and power plant in Białystok is to be partially met by two established plantations with an area of 130 ha, which can be expanded to 200 ha. It should be added that the demand for biomass from that CHP plant is estimated to be 4000 ha [Mystkowski 2010]. Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 103 Benefits and difficulties connected with management of crops of fast growing trees The development of alternative sources of raw wood material and an increase in the procurement of wood biomass from outside forest ecosystems has become a necessity. This concerns wood for industrial purposes and, to a greater and greater extent, wood biomass for energy purposes. The reasons for this are: –– the growing demand from the wood sector for raw wood material for material purposes, especially in periods of economic prosperity and wood deficits which then occur, –– the growing demand for final energy forcing the development of energy carriers alternative to fossil fuels, since the resources of traditional energy raw material are limited, –– the growing drive towards the relative reduction in wood harvesting in forests and expanding their ecological and social functions at the expense of their production function, which is connected with the protection of large forest areas within the Nature 2000 Programme [Bodył 2011]. It is estimated that at present relatively large unused reserves of wood biomass, especially as an energy carrier, are primarily found in plantation crops of fast-growing trees. However, putting them to use still requires the surmounting of many economic, technological, and organizational barriers. The as yet unexploited chances to gradually increase the potential of wood biomass are primarily found in Polish agriculture. Plantation crops of fast-growing trees in this sector can and should be treated not only as a source of biomass, but also as a stimulus for regional development, especially rural development, as the establishment of these crops on lower-quality soils (soils of low production), soils which are contaminated and not suitable for edible crops, fallow lands or degraded areas, is an additional source of income for farmers (very good and good soils, which account for 54% of total arable land in Poland, should be used only for the production of food and forage). Therefore, this can be a way to improve the economic performance of many farms. It also creates new jobs, which is especially important in underdeveloped areas, usually characterized by a high unemployment rate. The development of plantation crops of fast-growing trees in agriculture can also be a way to protect forest ecosystems from their excessive exploitation. Moreover, “energy” crops have the ability to accumulate contamination and over a few years they can clean the soil of heavy metals. The use of biomass from fast-growing trees as an energy carrier should also increase the degree of energy safety, especially locally in places where the biomass is produced, assuring a supply of energy, especially in areas where the power infrastructure is underdeveloped. The notion that there is potential demand for this energy carrier can be derived from the fact that approximately 1 M single houses in Poland are already heated by wood biomass [Sawicki 2012]. 104 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć Unfortunately, the market in biomass from fast growing trees is emerging relatively slowly (due to the time necessary for cultivated stands to reach their full yield capacity), the costs of the establishment, management and liquidation of such plantations are relatively high, and a return on the investment period is fairly long. The establishment of plantations is also most often discouraged by their (hitherto) low profitability in relation to traditional agricultural crops. In the opinion of specialists, in current conditions only very well-organized crops may be effective, i.e. crops which assure a high yield at relatively low production costs [Kwaśniewski 2011]. Assuming the anticipated further development of plantation crops of fast-growing trees in agriculture, one should remember that the allocation of too much land for these crops can pose some danger. Since the basic role of agriculture is to assure the food safety of the country (a food supply), the development of plantation crops should not limit the land area available for food and forage crops, for it consequently would lead to an increase in food and forage prices. As mentioned earlier, the market in biomass from fast-growing trees has a high development potential, which has not been exploited fully. The lines of its future development will be set mainly by the growing demand from the wood sector for wood for material purposes and the necessity to develop renewable energy source alteratives to fossil fuels, amongst which biomass plays an important role. Depending on their final form, legal regulations and economic tools (effective and pending), and especially their comprehensiveness, unambiguity, cohesion, and stability, will be the primary stimuli for or curbs to the development of this market (table 4). Brak wsparcia finansowego inwestycji w uprawy plantacyjne drzew szybkorosnących (dopłaty, kredyty preferencyjne) Najczęściej długi okres zwrotu zainwestowanych środków grożący utratą płynności finansowej plantatorów Most often a long period of return on invested capital, which may result in the loss of the financial liquidity of the planters Możliwość uprawy szybkorosnących drzew leśnych na haliznach, płazowinach oraz powierzchniach po drzewostanach zakwalifikowanych do przebudowy całkowitej tradycyjnych upraw rolniczych The possibility to cultivate fast-growing trees on failThe lowest profitability from the production of biomass from fast-growing trees, espeplaces, irregularly stocked open stands and areas where cially in relation to traditional agricultural crops previously stands were classified for complete conversion Niższa opłacalność produkcji biomasy z drzew szybkorosnących, szczególnie w odniesieniu do Relatywnie duża tolerancja siedliskowa i środowiskowa upraw plantacyjnych drzew szybkorosnących (gleby niewykorzystane dla uprawy żywności i pasz, grunty odłogowane, zdegradowane) The relatively high costs of the establishment, management and liquidation of plantation crops of fast-growing trees A relatively high tolerance of plantation crops of fast-growing trees as regards habitats and environment (soils which are not used for the cultivation of food and forage, fallow and degraded lands) Stosunkowo wysokie koszty założenia, prowadzenia i likwidacji upraw plantacyjnych drzew szybkorosnących prawa w odniesieniu do upraw plantacyjnych drzew szybkorosnących Znaczne obszary nieużytków w Polsce umożliwiające ich ewentualne wykorzystanie do produkcji biomasy z drzew szybkorosnących Considerable areas of fallow land in Poland, which facili- Lack of organizational and legal support for investors, instability of the law made tate their possible use for the production of biomass from in relation to plantation crops of fast-growing trees Brak wsparcia organizacyjnego i prawnego inwestorów, niestabilność stanowionego fast-growing trees Legislacja wspierająca rozwój źródeł biomasy drzewnej spoza ekosystemów leśnych Legislation supporting the development of sources of wood biomass from outside forest ecosystems Lack of financial support for investments in plantation crops of fast-growing trees (subsidies, preferential loans) 2 1 Bariery Barriers Możliwości Opportunities Tabela 4. Ważniejsze uwarunkowania rozwoju rynku biomasy z drzew szybkorosnących w Polsce – możliwości i bariery Table 4. Major conditions for the development of the market in biomass from fast-growing trees in Poland – opportunities and barriers Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 105 1 2 Stosunkowo niski stopień ryzyka inwestycyjnego w wypadku upraw energetycznych (inwestycje w odnawialne źródła energii uważa się za inwestycje o niskim stopniu ryzyka w długim okresie) A relatively low investment risk in the case of energy crops (investments in renewable energy sources are believed to be low risk investments in the long-term) Zagrożenia wynikające z prowadzenia upraw monokulturowych na dużych obszarach w lasach, zmniejszenie różnorodności biologicznej drzewostanów Threats stemming from managing monocultures on large areas in forests, the reduction of the biological diversity of stands Duże możliwości techniczne przetwarzania biomasy z drzew dostaw biomasy z drzew szybkorosnących szybkorosnących na cele materiałowe i jako nośnika energii Considerable technical possibilities of converting The lack of a comprehensive, developed ready market and an organized system biomass from fast-growing trees into materials and using of contracting the supply of biomass from fast-growing trees Brak kompleksowego, rozbudowanego rynku zbytu, zorganizowanego systemu kontraktacji it as an energy carrier Produkcja biomasy z drzew szybkorosnących zgodna z założonym celem, o określonych i pożądanych cechach, zgodna z wymaganiami odbiorcy Production of biomass from fast-growing trees in line with the set goal, a biomass of defined and desired properties and tailor-made Konieczność – w wypadku celowych upraw energetycznych o krótkiej rotacji – szybkiego wykorzystania zebranego surowca, duża wilgotność biomasy po zbiorze, jej duża objętość, trudne przechowywanie, magazynowanie i transport In the case of dedicated energy crops of a short rotation, there is a necessity for the quick use of harvested raw material; after harvesting, biomass is characterized by high moisture content, is bulky, difficult to store and transport The relatively high productivity of plantation crops of fast-growing trees in relation to forest plantations Relatywnie wysoka produktywność upraw plantacyjnych drzew szybkorosnących w odniesieniu do upraw leśnych w stosunku do innych rodzajów produkcji rolniczej Stosunkowo krótki cykl produkcyjny biomasy z drzew szybkorosnących (w relacji do tradycyjnych upraw leśnych) A relatively short production cycle of biomass from fast- Hitherto low competitiveness of plantation crops of fast-growing trees in relation -growing trees (in relation to traditional forest to other types of agricultural production Mała, jak dotychczas, konkurencyjność upraw plantacyjnych drzew szybkorosnących plantations) Tabela 4. Ciąg dalszy Table 4. Continued 106 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć 1 Source/Źródło: [Szostak et al. 2012] Możliwość prowadzenia upraw plantacyjnych drzew szybkorosnących na zasadzie współpracy z krajowymi i zagranicznymi firmami zajmującymi się ich zarządzaniem The possibilities of cultivating plantation crops of fast-growing trees in co-operation with domestic and foreign companies, which manage them Tabela 4. Ciąg dalszy Table 4. Continued Słabo rozpowszechniona wiedza specjalistyczna o prowadzeniu upraw plantacyjnych drzew szybkorosnących Little disseminated specialist knowledge of the management of plantation crops of fast-growing trees Brak rozwiniętego systemu informacji o podaży i popycie na biomasę z drzew szybkorosnących utrudniający podejmowanie decyzji inwestycyjnych The lack of a developed system of information on the supply of and demand for biomass from fast-growing trees, which hampers investment decisions Stosunkowo duże wymogi pielęgnacyjne upraw plantacyjnych drzew szybkorosnących Relatively high requirements as regards tending to plantation crops of fast-growing trees Brak odpowiednio rozwiniętej infrastruktury przetwórczej, magazynowej i rynkowej dla biomasy z upraw plantacyjnych drzew szybkorosnących (profesjonalnych maszyn do zbioru, specjalistycznego sprzętu do prowadzenia upraw) The lack of adequately developed processing, storage, and market infrastructure for biomass from plantation crops of fast-growing trees (professional harvesting machines, specialist equipment for plantation management) W rolnictwie – priorytet bezpieczeństwa żywnościowego kraju i zrównoważonego wykorzystania obszarów rolniczych In agriculture, there is the priority of the food safety of the country and the sustainable use of agricultural areas Brak odpowiednich powierzchni pod uprawy plantacyjne drzew leśnych, nieprzekazywanie Lasom Państwowym odpowiednich powierzchni przez Agencję Rynku Rolnego The lack of areas suitable for plantation crops of forest trees, as the Agricultural Market Agency does not transfer suitable areas to the State Forests Zbyt mało rozpoznane następstwa środowiskowe i krajobrazowe upraw plantacyjnych drzew szybkorosnących w rolnictwie 2 A Lack of knowledge of the environmental and landscape consequences of plantation crops of fast-growing trees in agriculture Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 107 108 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć Conclusions Over the last few years, the procurement of biomass from fast-growing trees has became a point of broad discussion and interest as observed in business practice. In subject literature, there is still a degree of ambiguity as regards the terms used and often unclear criteria for the classification of categories used within the field. This concerns the concept of “fast-growing trees” as well as the terms “plantation crops” and “plantation” (which most often relate to the place and entirety of activities, understood sensu lato, connected with the procurement of biomass from fast-growing trees, thus biomass originating from outside forest ecosystems). This ambiguity underlines the urgent need to standardize the terminology used at the level of both legal regulations and business practice. However, it is possible to capture common elements of the definitions „plantation” and „plantation crops of fast-growing trees”, namely that they are tree crops established with a view to obtaining a larger supply of wood biomass of a required quality in a relatively short period, that their permanent feature is their „artificial origin” from adequately-selected or genetically-modified tree species, and they are managed in the form of regular spacing and require tending and agrotechnical procedures. In the Polish economy, biomass from fast-growing trees is produced in two sectors, i.e. agriculture and forestry. These sectors have a large developmental potential as regards plantation crops of fast-growing trees. The potential of lands for dedicated crops for the power industry is determined to be 0.3–0.6 M ha. On the other hand, in agriculture, after a short period of interest in the management of crops of fast-growing trees in the period 2005–2008 (which was the result of economic factors, i.e. initially subsidies from the national budget, and later also from EU funds), in the following years a downward trend in the size of the area of such crops was observed. Recently, i.e. in the period 2010–2011, the area of plantation crops of fast-growing trees was approximately 11 thou. ha. In forestry, plantations of fast-growing trees play an insignificant role. They cover small areas, which are usually the remnants of plantations established in the mid-1970s. In 2011, the area of dedicated plantation crops of fast-growing trees in Poland was 13.7 thou. ha in agriculture and forestry together. Over the last few years, in the face of a growing demand for wood, wood biomass from plantation crops of fast-growing trees has become an alternative sourceof raw wood material from outside forest ecosystems. The wood from this source may be used for material and energy purposes; however, in business practice, wood biomass from plantation crops of fast-growing trees is treated mainly as a source of energy. The suitability of wood biomass from plantation crops for material and energy purposes stems from both its properties and the existing technologies used for its processing for material and energy purposes. Despite the challenges which the Polish power industry currently face, the official assumption of the Polish economic policy is that the consumption of wood Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 109 for energy purposes should not cause a deficit for industrial processing. The combustion of wood should be the last form of its use after it has been used as material and multiply recycled, for the effectiveness of raw wood material conversion into wood products, especially those of high value added, is many times greater than in the case of its conversion into energy, even if it is „green energy”. Therefore, the need to increase the wood supply, so as to avoid the dilemma of its use for material or energy purposes, is the rationale behind the optimum use of all the available resources of various biomass types in business practice, as well as an increase in the biomass harvesting of plantation crops of fast-growing trees. The lines of the future development of the market in biomass from fast-growing trees will be set mainly by the growing demand from the wood sector for wood for material purposes and the need to develop renewable energy sources as an alternative to fossil fuels, amongst which biomass plays an important role. Depending on their final form, legal regulations and economic tools (effective and pending), and especially their comprehensiveness, unambiguity, cohesion, and stability, will be the primary stimuli for or curbs to the development of the market, for it is conditioned, to a great extent, by active financial and legal support, assuring the profitability of the process of harvesting and processing biomass from fast-growing trees. Therefore, the main and most important task is to develop, at a national level as well as business entity level, a systems approach to solving existing and future issues connected with the operation of this market. References Bartczak M. [2008]: Czy kupimy, czyli miejsce energetyki zawodowej w kolejce do hurtowni z wierzbą energetyczną. Mat. konf.: Wdrażanie przepisów UE regulujących wykorzystanie odnawialnych źródeł energii w wybranych krajach członkowskich ze szczególnym uwzględnieniem zagadnienia wykorzystania biomasy, Kalisz Bodył M. 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Mat. konf.: Uprawa plantacyjna drzew szybko rosnących alternatywą dla leśnictwa wielofunkcyjnego i przemysłu, Kadyny 112 Aleksandra Szostak, Gabriela Bidzińska, Ewa Ratajczak, Magdalena Herbeć BIOMASA DRZEWNA Z UPRAW DRZEW SZYBKOROSNĄCYCH JAKO ALTERNATYWNE ŹRÓDŁO SUROWCA DRZEWNEGO W POLSCE Streszczenie Prowadzenie upraw plantacyjnych drzew szybkorosnących i ich rozwój ma duże znaczenie nie tylko dla oszczędności surowca drzewnego z lasu i zwiększenia dywersyfikacji źródeł energii, ale przez swoją specyfikę (najczęściej są to małe i średnie firmy zlokalizowane blisko odbiorcy i korzystające z lokalnych zasobów) może i powinien dynamizować rozwój ekonomiczno-społeczny na poziomie lokalnym. Uprawy te mogą i powinny być traktowane zwłaszcza jako nowa dziedzina produkcji rolniczej, dodatkowe źródło dochodów i efektywne wykorzystanie odłogowanej ziemi. Pomimo tych aspektów rynek biomasy z drzew szybkorosnących jest jednak nadal stosunkowo mało rozpoznany. Celem podjętych badań było przeprowadzenie wieloaspektowej analizy rynku biomasy z drzew szybkorosnących w Polsce, w tym głównie przeznaczonej na cele energetyczne. Zakresem podmiotowym badania objęły głównych uczestników rynku biomasy z upraw plantacyjnych drzew szybkorosnących w Polsce: to jest: rolnictwo leśnictwo oraz sektor energetyczny. Zakres czasowy badań obejmował zasadniczo lata 2010–2011. Proces badawczy o charakterze desk research uzupełniony został badaniami bezpośrednimi obejmującymi dostawców i odbiorców biomasy drzewnej z drzew szybkorosnących, a także jako dodatkowe możliwe źródło informacji z zakresu analizowanej problematyki – jednostki administracji publicznej. Z przeprowadzonych badań wynika, że w polskiej gospodarce miejscem powstawania biomasy z drzew szybkorosnących są dwa sektory: rolnictwo i leśnictwo. Sektory te posiadają duży potencjał rozwojowy w zakresie upraw plantacyjnych drzew szybkorosnących. Potencjał gruntów dla upraw celowych dla energetyki określany jest na 0,3–0,6 mln ha. Tymczasem w rolnictwie, po krótkim okresie zainteresowania prowadzeniem upraw drzew szybkorosnących w latach 2005–2008, spowodowanego przesłankami ekonomicznymi, tj. początkowo wsparciem z budżetu krajowego, a później również z funduszy unijnych, w kolejnych latach pojawiły się tendencje spadkowe wielkości powierzchni tego rodzaju upraw. W ostatnim okresie, tj. w latach 2010–2011, powierzchnia upraw plantacyjnych drzew szybkorosnących wynosiła około 11 tys. ha. W leśnictwie plantacje drzew szybkorosnących pełnią znikomą rolę. Są to niewielkie powierzchnie, będące na ogół pozostałością po plantacjach zakładanych w połowie lat siedemdziesiątych ubiegłego wieku. Łącznie w Polsce, w rolnictwie i leśnictwie, powierzchnia celowych upraw plantacyjnych drzew szybkorosnących w 2011 roku wynosiła 13,7 tys. ha. Możliwości systematycznego zwiększania potencjału biomasy drzewnej istnieją przede wszystkim w polskim rolnictwie. Uprawy plantacyjne drzew szybkorosnących w tym sektorze mogą i powinny być traktowane jako stymulator rozwoju regionalnego, szczególnie obszarów wiejskich. Wykorzystanie pod te uprawy gleb gorszej jakości (nisko produkcyjnych), zanieczyszczonych i nienadających się do uprawy roślin jadalnych, ziemi odłogowanej lub terenów zdegradowanych jest bowiem dla rolników dodatkowym źródłem dochodów. Może być sposobem na poprawę efektywności ekonomicznej wielu gospo- Wood biomass from plantations of fast-growing trees as an alternative source of wood raw material ... 113 darstw. Stwarza również nowe miejsca pracy, co jest szczególnie ważne na terenach słabo rozwiniętych, charakteryzujących się z reguły wysoką stopą bezrobocia. Kierunki przyszłego rozwoju rynku biomasy z drzew szyborosnących wyznaczać będą głównie rosnące potrzeby sektora drzewnego na drewno do przerobu materiałowego i konieczność rozwoju alternatywnych wobec paliw kopalnych odnawialnych źródeł energii, wśród których biomasa drzewna odgrywa istotną rolę. Stymulująco lub destymulująco, w zależności od ich ostatecznego ukierunkowania, na rozwój tego rynku będą wpływać przede wszystkim regulacje prawne i instrumenty ekonomiczne (już obowiązujące i przygotowywane), ich kompleksowość, jednoznaczność, spójność i stabilność. Rozwój rynku biomasy z drzew szybkorosnących jest bowiem w dużym stopniu uwarunkowana aktywnym wsparciem finansowym i prawnym, zapewniającym opłacalność procesu jej pozyskiwania i przetwarzania. Główną kwestią i najważniejszym zadaniem jest zatem wypracowanie zarówno na poziomie krajowym, jak i na poziomie poszczególnych podmiotów gospodarczych, systemowego podejścia do rozwiązania już istniejących i przyszłych problemów funkcjonowania tego rynku. Acknowledgements This article contains some of the results of research funded by the Ministry of Science and Higher Education [Szostak et al. 2012] carried out in 2012 in the Wood Industry Economics Department of the Institute of Wood Industry Wood Technology. Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.057.08 Milena Ratajczak-Mrozek, Magdalena Herbeć22 ACTORS-RESOURCES-ACTIVITIES ANALYSIS AS A BASIS FOR POLISH FURNITURE NETWORK RESEARCH The aim of the article is to identify the specifics of the furniture industry based upon the example of Poland and with the application of the industrial network approach. In the article, the ARA (Actors-Resources-Activities) model is adopted as the basic framework developed within the industrial network approach. This in turn allows for the identification of the interdependencies between important entities (actors), resources and activities influencing this industry, the main entities within the industry, the surrounding business environment as well as their characteristics. A special emphasis is put on the entities from the environment surrounding the furniture industry so as to include some significant factors influencing it – both in a positive and negative sense. Keywords: business network, industrial network approach, network relationships, cooperation, ARA model, furniture industry, furniture industry environment Introduction Due to transactions, formal and informal relationships, practically every entity to a varying extent is linked with others. The essence of business enterprise is of course tied to constant interactions and trade exchange with other entities on the market and „firms should not be seen in isolation but as being connected in business systems” [Ritter et al. 2004]. Moreover, due to increasing competitive pressures and dynamic changes occurring within their business environments, companies may not achieve their goals if they limit their strategies only to internal development. For this reason, it is important to move towards close cooperation and network relationships that Milena Ratajczak-Mrozek, Poznan University of Economics, Poznan, Poland e-mail: [email protected] Magdalena Herbeć, Wood Technology Institute, Poznan, Poland e-mail: [email protected] 116 Milena Ratajczak-Mrozek, Magdalena Herbeć can bring equally beneficial or perhaps even better results than “pure” competition [Ratajczak-Mrozek 2013]. Significant benefits flowing from cooperation and network relationships are important from the perspective of firms (at least due to an improvement in the market results achieved [Håkansson, Snehota 1995; Gadde, Snehota 2000; Ritter et al. 2004; Ratajczak-Mrozek, Małys 2012; Ratajczak-Mrozek 2012a]), as well as specific industries or the economy as a whole (improvement in competitiveness). For this reason, an analysis of the specifics of industry sectors from a network perspective is also important for supporting regulatory ties. In this article the focus of such an analysis is the furniture industry, an analysis which is strongly justified. The furniture market in Poland is an important market industry which drives many other goods markets. At the same time, the production of furniture is one of the wood industries which contributes the most to the country’s economy. In 2011, the furniture industry accounted for almost 1% of gross output and gross value added (conversely the wood industry accounted for 2.9% and 1.9% respectively) [CSO 2012c]. Sold furniture production in 2012 amounted to 29.7 m PLN, i.e. 2.5% of sold industry production [CSO 2012c]. The furniture industry’s leading position within the wood sector is demonstrated by the fact that it accounted for 32% of sold production in 2012 and 47% of the average paid employment in the furniture industry & wood sector in 2011 (144.3 k people). For many years, furniture has been almost the flagship item amongst Polish exports. In 2012, the share of furniture in exports amounted to 4.3% and they occupied 5th place in the ranking of the value of goods exported from Poland. On a global scale, the value of exported furniture (3%) places Poland in 4th position [WTI estimates; EPF 2011; Adamowicz, Wiktorski, 2010]. Moreover, Poland is among the leading furniture producers in the world. The value of furniture produced is estimated to be 9th in world rankings (2009) and 4th in Europe (2010) [EPF 2011; Adamowicz, Wiktorski 2010]. The analysis of the specifics of the furniture industry which is usually carried out is done so in the form of a report based upon industry data [Ratajczak et al. 2003; Adamowicz, Wiktorski 2006; Ratajczak et al. 2008] or descriptions of entities from the industry [Osiecka 2009]. There is very little analysis available regarding the importance of entities from the surrounding business environment [Ratajczak 2013]. At the same time, the importance of a complex analysis of the specifics of the industry should be clearly underlined. An analysis conducted from the perspective of the relationship at entity level (including the surrounding business environment), resources, or joint activities, provides an insight into the factors influencing management decisions at firm level or indeed the regulatory decisions pertaining to this field of the economy. As a result, the aim of the article is to identify the specifics of the furniture industry based upon the example of Poland and with the application of the industrial network approach, which as a result allows for the identification of the interdepen- Actors-resources-activities analysis as a basis for Polish furniture network research 117 dencies between important entities (actors), resources and activities influencing this industry. A special emphasis is put on the entities from the environment surrounding the furniture industry so as to include some significant factors influencing it – both in a positive and negative sense. Theoretical background The industrial network approach to defining a business network (industrial network approach) is linked to research carried out by the Industrial Marketing and Purchasing Group [IMP Group]. This concept stresses the significance of all the formal and informal, direct and indirect contacts (network relationships) a firm has with the entities in its surrounding environment which constitute an extended network. A relationship is developed through interactions, cooperation between entities [Easton 1992]. It may be established with different groups of entities (such as customers, suppliers, complementors, influential entities and competitors [Hollensen 2003; Ritter et al. 2004]). A business network (an industrial network) is a set of repetitive transactions based upon structural and relational formations with dynamic boundaries comprising interconnected elements (actors, resources and activities) [Todeva 2006]. A system of relationships is often characterised as being decentralised and largely informal, although it may also emerge in a strategic, formal manner. The business network is an effect of historical, mainly long-term close cooperation and a series of interactions going beyond single buy-sell transactions, which in turn create cooperation norms and build trust [Turnbull et al. 1996; Ford et al. 1986]. The basic framework developed within the industrial network approach is the ARA model (Actors-Resources-Activities) [Håkansson, Snehota 1995; Håkansson, Johanson 1992]. According to the ARA model, relationships are associated with the simultaneous exchange and adaptation of input and output resources, as well as activities (participation in events and performing business functions within the value chain) between cooperating participants of the network. Therefore, they are made up of actor bonds, activity links and resource ties, which create three overlapping networks [Lenney, Easton 2009]. Actor interdependencies are represented by the mutual dependency and interpersonal links developed between two interacting partners. The resources within resource interdependencies may be exchanged, mutually adapted, accumulated or even created. In this way, not only the individual resources are analysed but also those which result from interaction patterns between two or more actors. Finally, the activity interdependencies are represented by joint operations, activity participation and coordinated behaviour (which in turn may be important for the effectiveness of a network structure) [Todeva 2006]. In the case of the ARA model, it has to be made clear who the actors are, what their activities are and with which resources they interact when analysing data and network structure [Lenney, Easton 2009]. 118 Milena Ratajczak-Mrozek, Magdalena Herbeć The idea of Actors, Resources and Activities makes up part of the network picture [Henneberg et al. 2006]. The network picture refers to the views of the network held by participants in that network [Ford et al. 2002; Henneberg et al. 2006]. This picture is important because it forms the basis for their strategy analysis and development. Conceptual framework and the methodology In the article, the industrial network approach and ARA model are adopted in order to analyse the specifics of the furniture industry which makes up the conceptual framework (fig. 1). Source: Authors’ own work Źródło: Opracowanie własne Fig. 1. Conceptual framework Rys. 1. Ramy koncepcyjne Fig. 1 shows the ARA model linking actors with resources and activities from both the furniture industry and the environment outside this industry, and the interactions (creating relationships) between them. In keeping with the adopted conceptual framework, firms (actors) operating in the furniture industry have various relationships – both with entities from the industry as well as from outside it (firms, but also administrative or education institutions, for example). This creates the actor level of the furniture industry specifics analysis. Actors’ interactions are accompanied by interactions on the level of resources and activities. These include resource ties and activity links both within the furniture industry, as well as between this industry and the surrounding environment. In this article, we sequentially analyse the elements presented as part of the conceptual framework. First we analyse the specifics of the furniture indus- Actors-resources-activities analysis as a basis for Polish furniture network research 119 try, then we describe the actors from the industry, actors from the surrounding environment as well as the resource characteristics and the interdependence of activities. The basis for the presented discussion is the analysis of secondary sources concerning data from the furniture industry. A comparative analysis of sectorial statistical data essentially covers the years 2011–2013. The specifics of actors – the furniture industry The main focal actors in the Polish furniture network structure are the firms in the industry. Among them, due to the scope of the core business and on the basis of the Polish Classification by Activity (the fourth level of the 2007 NACE classification is in line with the European NACE Rev. 2) the following can be distinguished [Rozporządzenie Rady Ministrów 2007]: –– manufacturers of office and shop furniture (C 31.01), –– manufacturers of kitchen furniture (C 31.02), –– manufacturers of mattresses (C 31.03), –– manufacturers of other furniture (C 31.09). Firms classified as producers of “other furniture” are dominant in the entity structure of the furniture industry. Thus, among the actors of the furniture industry network, manufacturers of room furniture, bedroom furniture, garden furniture and other upholstered furniture should be defined, as well as firms providing services associated with the production of furniture, such as painting and upholstery. In the first half of 2013, actors from this group of entities (others) made up almost half (45%) of the overall entities in the furniture industry. Table 1 contains a detailed structure of the entities in the furniture industry per employment group in the first half of 2013. Upon examining the characteristics of the actors from the furniture industry, it should be noted that there is a large degree of fragmentation of manufacturers. In the first half of 2013, there were almost 24 thousand entities of which 92% of firms employed up to 9 people and 6% between 10 to 49 employees. Only 2% were large or very large firms [CSO 2013a]. Such a structure implies both problems with management and, it would seem, should encourage the formation of network structures with the view to at least increasing bargaining power or gaining access to resources. In 2011, micro and small firms employing up to 49 people generated 21% of the value of sold production of the furniture industry, at the same time making up 27% of average paid employment in the furniture industry [own calculations; CSO 2012b; CSO 2012c]. It is typical for the furniture manufacturing industry that small upholsterers and carpentry firms are dominant, where work is often focused on providing services [Ratajczak 2009]. Based upon accessible reporting and knowledge of the industry, it can be assumed that approximately 2000 firms are solely engaged in furniture production (without services). 120 Milena Ratajczak-Mrozek, Magdalena Herbeć This large share of service activities as well as the linking of services with production translates into the characteristic of activities interdependence. Table 1. Number of firms in the furniture industry by employment groups in the first half of 2013 Tabela 1. Liczba podmiotów w przemyśle meblarskim według grup zatrudnienia w pierwszym półroczu 2013 roku Specification Employment group Wyszczególnienie Furniture production, including: Produkcja mebli, w tym: ––manufacturers of office and shop furniture produkcja mebli biurowych i sklepowych ––manufacturers of kitchen furniture produkcja mebli kuchennych ––manufacturers of mattresses produkcja materaców ––manufacturers of other furniture produkcja pozostałych mebli Total furniture production Razem produkcja mebli Grupy zatrudnienia Total 0–9 10–49 50–249 250 = > 5940 5535 334 63 8 6903 6634 240 28 1 191 165 18 5 3 10594 9412 867 234 81 23628 21746 1459 330 93 As per the 2007 NACE classification Według klasyfikacji PKD 2007 Source: Authors’ own work based upon [CSO 2013a] Źródło: Opracowanie własne na podstawie [CSO 2013a] It is worthwhile noting that in Poland in 2011 the coefficient of sold production concentration in the furniture industry amounted to 0.784 and was close to the level of the manufacturing sold production index for the country, which was equal to 0.8051. Here an example can be the results of the study carried out for the group of 1745 furniture firms from 2011. In this group (of 1745 furniture firms), 50% of sold production was attributed to 2% of the entities employing more than 9 persons, whilst 13% of firms made up 80% of the sold production [CSO 2012b]. Such an entity structure can additionally promote the development of closer relations and cooperation between firms. In particular, the level of technological advancement among firms producing furniture is differentiated. Among others, this is related to the significant differentiation in the level of technological advancement of products as well as production standards in specific industries (e.g. a lower level of technological advancement in upholstered furniture) and gro1 The coefficient of sold production concentration is calculated according to an interpolative formula, constructed on the basis of the Lorenz curve. The coefficient assumes values between 0 and 1; the higher the concentration, the closer the value of this coefficient is to 1 [CSO 2012a]. Actors-resources-activities analysis as a basis for Polish furniture network research 121 ups of firms (outstanding due to the size of business entities which is connected to investment activity). Another important issue for network structures in furniture manufacturing is the fact that there is an increasing number of foreign entities among those actors making up the network. REGON (National Register of Business Entities) registry data shows that whilst the number of furniture manufacturers fell between 2011 and mid 2013 (a decrease of approx. 11%), there was an increase in the number of foreign-owned firms in this period (an 8% increase or 252 firms, table 2). Additionally, foreign actors in the furniture industry are also present in firms with mixed ownership, i.e. domestic and foreign. During the examined period, 230 such firms were identified. This is evidence of the trans-regional importance of the Polish furniture industry which can influence resource structures and the activities of furniture networks. In this group of actors, as in the whole furniture industry in Poland, firms engaged in the production of so-called other furniture are dominant. Their share of firms which are the property of foreign investors is close to 70%. However, the total number of furniture firms under foreign ownership does not exceed 1% [CSO 2013a]. It is estimated that approx. 70% of firms with foreign capital in the furniture industry employ at least 10 employees and generate 30% of average paid employment in the furniture industry [CSO 2012a]. Total 23628 10594 191 6903 5940 Razem Public Sector 4 1 0 0 3 Sektor publiczny Źródło: Opracowanie własne na podstawie [CSO 2013a] Source: Authors’ own work based upon [CSO 2013a] Według klasyfikacji PKD 2007 Polish Classification by Activity (NACE) 2007 Razem produkcja mebli Total furniture production Produkcja pozostałych mebli Production of other furniture Produkcja materaców Production of mattresses Produkcja mebli kuchennych Production of kitchen furniture Produkcja mebli biurowych i sklepowych Production of shop and office furniture Produkcja mebli, w tym: Furniture production including: Sektor prywatny Private Sector 9987 182 6836 5747 krajowych osób fizycznych 23624 22752 10593 191 6903 5937 prywatna krajowa pozostała private domestic other 384 267 1 42 74 osób zagranicznych foreign investors 252 176 6 17 53 68 41 1 5 21 w tym: including: 40 29 0 1 10 mieszana z przewagą własności osób zagranicznych 80 57 0 2 21 mixed, dominated by foreign individuals Podmioty w przemyśle meblarskim i forma własności mixed, dominated by domestic individuals mieszana z przewagą własności krajowych osób fizycznych Wyszczególnienie Entities in the Furniture Industry & types of ownership mixed, dominated by private domestic other Details domestic individuals Tabela 2. Podmioty w przemyśle meblarskim według formy własności Table 2. Entities in the furniture industry & types of ownership mieszana z przewagą własności prywatnej krajowej pozostałej mieszana z brakiem przewagi któregokolwiek rodzaju własności mixed, where neither form of ownership is dominant 42 33 1 0 8 122 Milena Ratajczak-Mrozek, Magdalena Herbeć 123 Actors-resources-activities analysis as a basis for Polish furniture network research The share of foreign capital among actors from the furniture industry is evident also in the presence of numerous production plants owned by foreign concerns. Foreign actors playing an important role in the Polish furniture industry network structure come from various countries, such as Sweden, the USA and Belgium. The largest foreign economic entity is Swedwood, which is the IKEA production firm. Table 3 shows a group of the largest furniture producers in terms of net income from sold production, goods and materials in Poland, taking into account the type of ownership (in terms of the country of origin of the firms’ capital) in 2012. Table 3. The largest furniture producers (firms and groups) in terms of net income from sold production, goods and materials in Poland in 2012 by the type of ownership Tabela 3. Najwięksi producenci mebli (firmy i grupy firm) w Polsce według przychodów netto ze sprzedaży produktów, towarów i materiałów w 2012 roku z uwzględnieniem form własności No. Firm Lp. 1 2 3 4 5 6 7 8 9 10 Firma Swedwood Poland Sp. z o.o. Swedwood Poland Sp. z o.o. Black Red White Group Grupa Black Red White The Furniture Group Szynaka Grupa Meblowa Szynaka Com.40 Limited Sp. z o.o. Com.40 Limited Sp. z o.o. IMS Group Grupa IMS Nowy Styl Sp. z o.o. Nowy Styl Sp. z o.o. Furniture Factories Forte SA Fabryki Mebli Forte S.A. Dendro Poland Ltd. sp. z o.o. Dendro Poland Ltd. sp. z o.o. Hilding Anders Poland Sp. z o.o. Hilding Anders Polska Sp. z o.o. Furniture Factory Bodzio Sp. j. Fabryka Mebli Bodzio Sp. j. Net income [mio PLN] Polish capital Participation of foreign capital 3 997.3 – 1 550.0 – 682.3 – 625.1 – 458.0 – 440.2 – 434.4 – 335.9 – 316.6 – 309.8 – Przychód netto [mln PLN] Kapitał polski Udział kapitału zagranicznego – occurrence exists/zjawisko występuje Source: Authors’ own work based upon [Hryniewicki 2012] and firm websites Źródło: Opracowanie własne na podstawie [Hryniewicki 2012] i stron internetowych firm 124 Milena Ratajczak-Mrozek, Magdalena Herbeć It is important to point out that among the 10 largest firms and groups producing furniture, 4 include foreign capital. This not only implies the possibility of utilising modern techniques and technologies thanks to higher levels of investment, but also the introduction of new management practices. It is estimated that medium and large enterprises are the most innovative and competitive furniture firms and it is they which attract the most foreign investment [Ratajczak 2009]. Moreover, it seems that international cooperation can, in comparison to local cooperation, generate additional benefits for a firm, including the transfer of advanced knowledge, good practices or know-how [Ratajczak-Mrozek 2012b]. The specifics of actors – the environment surrounding the furniture industry Among the actors cooperating with furniture manufacturers are firms from both the wood sector (e.g. sawnwood producers, producers of wood-based panels) and other sectors (e.g. suppliers of tools, machinery & equipment, components and accessories, firms from the chemical and textile industries as well as IT). An attempt to identify all actors from the environment surrounding the furniture industry is presented in fig. 2. The characteristics of the main actors, resources and interdependent activities which are important from the perspective of cooperation and networks in the furniture industry are shown in table 4. Actors-resources-activities analysis as a basis for Polish furniture network research i in.) Source: Authors’ own work based upon [Ratajczak 2013] Źródło: Opracowanie własne na podstawie [Ratajczak 2013] Fig. 2. Actors from network structures surrounding the furniture industry Rys. 2. Aktorzy struktur sieciowych w otoczeniu przemysłu meblarskiego 125 Branża meblarska: producenci mebli i usługodawcy (zakłady stolarskie, tapicerskie) Furniture industry: furniture producers & service providers (joiners & upholsterers) Typ podmiotu 1 Type of entity − Duża koncentracja produkcji w nielicznych dużych firmach kształtujących rynek mebli, przy dominacji mikro i małych przedsiębiorstw. − Duży wskaźnik koncentracji produkcji sprzedanej. − Duży potencjał produkcyjny i rezerwy w jego wykorzystaniu. − Znaczny udział firm posiadających certyfikaty kontroli pochodzenia produktu FSC CoC (Forest Stewardship Council Chain of Custody) oraz ISO (Międzynarodowa Organizacja Normalizacyjna). − Udział podmiotów z kapitałem zagranicznym. − Mniejsza podatność innowacyjna małych firm − Large concentration of production in a few large firms shaping the furniture market, dominated by micro & small firms. − Large coefficient of sold production concentration. − Large production potential and reserves. − Firms with FSC CoC (Forest Stewardship Council Chain of Custody) and ISO (International Organisation for Standardisation) certificates are predominant. − Entities with foreign capital. − Small firms are less inclined to innovate. Actors Aktorzy 2 najbardziej nowoczesny w przedsiębiorstwach z kapitałem zagranicznym). − Zależność od surowca drzewnego − Sporadyczne korzystanie z outsourcingu pomimo złożoności procesów produkcji, dotyczy to zwłaszcza mikro i małych przedsiębiorstw. − Mała potrzeba wśród samych aktorów tworzenia sieci (takie struktury tworzy się w większości przypadków z inicjatywy odgórnej) Działania 4 Activities − Differentiated level of modern − Sporadic utilisation of outsourcing equipment (less modern in smaller despite the complex nature of firms, whilst the most modern in firms production processes, applies with foreign capital). especially to micro and small firms. − Dependence on wood raw materials. − Little requirement amongst the actors − Zróżnicowany stopień nowoczesności forming the network (such structures aparatu wytwórczego (mniej nowoczesny are formed in most cases on a topw mniejszych przedsiębiorstwach, down basis). Zasoby 3 Resources Tabela 4. Charakterystyka struktur sieciowych branży meblarskiej z uwzględnieniem aktorów, zasobów i działań Table 4. Characteristics of the Polish furniture industry including actors, resources and activities 126 Milena Ratajczak-Mrozek, Magdalena Herbeć 4 Dostawcy surowca i materiałów: producenci płyt drewnopochodnych Dostawcy surowca i materiałów: przedsiębiorstwa tartaczne − Atrakcyjna oferta inwestycyjna dla inwestorów zagranicznych. − Współpraca z zapleczem badawczo-rozwojowym z kraju pochodzenia kapitału kosztem współpracy z krajowym zapleczem badawczo-rozwojowym − Attractive investment opportunities for foreign investors. − Cooperation with R&D facilities in the country of the origin of the capital at the expense of cooperation with domestic R&D facilities. gospodarczych (wokół bazy surowcowej) − Stosunkowo niski poziom nowoczesności − Niska skuteczność w przyciąganiu o najczęściej niewielkiej skali produkcji. aparatu wytwórczego, stosowanych inwestorów zagranicznych. − Znaczący potencjał produkcyjny technik i technologii. − Mimo dużego rozproszenia aktorów, i rezerwy w jego wykorzystaniu. − Wysoki stopień krajowej (zwłaszcza małych) i wspólnego − Mała podatność na innowacje samowystarczalności w sferze problemu związanego z zaopatrzeniem zaopatrywania w surowiec drzewny. w surowiec, niska skłonność do − Małe zasoby kapitałowe przedsiębiorstw zrzeszania się nie pozwalające na finansowanie rozwoju − Relatively large share of entities − High level of self-supply of domestic wood raw material. with foreign capital with a strong dependence on this type of investment − Utilisation of foreign technologies on a large scale (particularly in the case in the particle board production of the production of oriented strand industry. boards (OSB) and medium density − Significant production concentration. board (MDF); limited use of self− Entities with a differentiated developed technologies and products inclination to innovate in the with a low degree of modernisation production of various wood-based (e.g., the production of plywood). panels (low in the case of hardboard − Significant production potential and plywood producers). − Relatywnie duży udział podmiotów and unused reserves (fibreboard, kapitału zagranicznego i duże plywood). uzależnienie od niego w branży płyt − Significant capital potential (mainly in wiórowych. the particle board industry) facilitating − Znaczna koncentracja produkcji. self-growth. 3 Suppliers of resources and raw materials: wood-based panels manufacturers 2 − Large dispersion of entities (around − Relatively low level of modernisation, − Low effectiveness in attracting resource bases) often with small scales utilised techniques and technologies. foreign investors. of production). − High level of domestic self-sufficiency − Despite the large dispersion of − Significant production potential and in terms of industrial roundwood actors (especially small ones) and unused reserves. supplies. the common problem of obtaining − Little inclination to innovate. − Small capital resources prevent firms raw materials, there is a limited − Duże rozproszenie podmiotów from developing. inclination to form associations. Suppliers of resources and raw materials: sawmills 1 Tabela 4. Ciąg dalszy Table 4. Continued Actors-resources-activities analysis as a basis for Polish furniture network research 127 3 − Wysoki stopień samozaopatrzenia w krajowy surowiec drzewny. − Wykorzystywanie na dużą skalę zachodnich rozwiązań technologicznych (zwłaszcza w produkcji płyt wiórowych zorientowanych – OSB i suchoformowanych płyt pilśniowych – MDF); mało nowoczesne, nieliczne własne rozwiązania technologiczne i produktowe (przemysł sklejek). − Znaczny potencjał produkcyjny i rezerwy w jego wykorzystaniu (płyty pilśniowe, sklejki). − Znaczący potencjał kapitałowy (głównie w branży płyt wiórowych) służący samorozwojowi 2 − Podmioty o zróżnicowanej podatności innowacyjnej w produkcji poszczególnych płyt drewnopochodnych (niska – zwłaszcza producentów płyt pilśniowych twardych, sklejek) podnoszenia konkurencyjności branży 4 włókiennicze produkujące materiały obiciowe od miejsca uprawy surowca (większość surowca sprowadzana z zagranicy). − Koncentracja wytwórców w dużych okręgach przemysłowych (produkcja opłacalna w dużej skali) − Uzależnienie od importowanych surowców (w kraju uprawia się tylko len). − Przemysł wysoko pracochłonny. − Konkurencyjne cenowo produkty zagraniczne mające relatywnie duży udział w rynku (m.in. produkty z Azji Południowo-Wschodniej) Suppliers of resources − Location of the entities is independent − Dependence on imported raw material − Inability to cooperate and utilise source of raw materials (the majority (linen is the only domesticallythe effects of cooperation with and raw materials: of the resource is imported from produced raw material). competitors (coopetition) in order textile firms producing abroad). − Highly labour intensive industry. to increase the competitiveness materials for − Concentration of producers in large − Price competitive foreign products of the industry. upholstery − Nieumiejętność zrzeszania się Dostawcy surowca industrial centres (production is have a relatively large market share i wykorzystania efektów współpracy i materiałów: profitable on a large scale). (among others, products from southz konkurentami (kooperencja) do przedsiębiorstwa − Lokalizacja podmiotów niezależna eastern Asia). 1 Tabela 4. Ciąg dalszy Table 4. Continued 128 Milena Ratajczak-Mrozek, Magdalena Herbeć Dostawcy surowca i materiałów: branża chemiczna, w tym producenci farb i lakierów Suppliers of resources and raw materials: the chemical industry, including producers of paint and varnish Dostawcy surowca i materiałów: pozostałe przedsiębiorstwa produkujące materiały obiciowe (w tym ze skór, tworzyw sztucznych i in.) Suppliers of resources and raw materials: other firms producing upholstery (including leather, artificial materials and others) 1 Tabela 4. Ciąg dalszy Table 4. Continued − Dominacja mikro i małych przedsiębiorstw. − Koncentracja produkcji w średnich i dużych przedsiębiorstwach. − Stosunkowo duży udział kapitału zagranicznego w firmach − Dominated by micro and small firms. − Concentration of production in small and medium-sized firms. − Relatively large share of foreign capital in firms. − Przewaga średnich i dużych firm (produkcja opłacalna w dużej skali) w procesach produkcji i zarządzania. − Wykwalifikowana kadra. − Zasobna baza surowcowo-materiałowa. − Duże zróżnicowanie potencjału przedsiębiorstw − Wysoki udział eksportu do krajów UE. − Znaczny udział importu farb i lakierów dla branży meblarskiej (nawet 70%). − Produkcja na dużą skalę półproduktów wykorzystywanych przez liczne działy przemysłu – potencjał wymiany − Znaczny udział importu surowców do produkcji materiałów obiciowych. − Ścisła współpraca z meblarstwem będącym głównym odbiorcą przy nielicznych działaniach zmierzających do zrzeszeń − Significant share of imports in resources required for the production of upholstery materials. − Close cooperation with the furniture industry which is the main recipient of the few efforts to form associations. 4 − Modern technological solutions − Large share of exports to EU in production and management countries. processes. − Significant share of imported paint − Qualified management team. and varnish for the furniture industry − Rich resource base. (as much as 70%). − Differentiated level of potential among − Large-scale production of intermediate firms. goods utilised by numerous industry − Nowoczesne rozwiązania technologiczne sectors – potential for exchange − Zróżnicowana konkurencyjność wyrobów. − Krajowa baza surowcowa niekonkurencyjna cenowo w stosunku do surowców z importu 3 − Firms with foreign capital. − Differentiated competitiveness − Dominance of medium and large of goods. firms (production profitable on a large − The domestic resource base is not scale). price competitive in comparison − Udział firm z kapitałem zagranicznym. to imports. 2 Actors-resources-activities analysis as a basis for Polish furniture network research 129 Dostawcy surowca i materiałów: producenci maszyn i urządzeń − Wyspecjalizowane firmy − Producenci wyrobów high-tech. − Relatywnie duży udział kapitału zagranicznego − Elastyczne linie produkcyjne (przezbrajane dzięki programom komputerowym). − Urządzenia umożliwiające automatyzację i integrację procesów produkcji (np. Wieloczynnościowe, komputerowo sterowane urządzenia numeryczne – Computerized Numerical Control – CNC) − Elastic production lines (re-tooled thanks to computer software). − Equipment facilitating the automation and integration of production processes (e.g. Computerised Numerical Control – CNC). − Coraz większe zainteresowanie meblarstwa maszynami i urządzeniami zwiększającymi automatyzację i integrację produkcji – potencjał wymiany − Increasing interest throughout the furniture industry in machinery and equipment increasing the automation and integration of production (potential for exchange). − Brak instytucji otoczenia biznesu działających na rzecz tych przedsiębiorstw. − Współpraca z odbiorcami nie tylko z meblarstwa, ale również z innych branż. − Mała intensywność działań zmierzających do zrzeszeń pomimo relatywnie dobrych. potencjalnych warunków współpracy z przedsiębiorstwami z innych branż 4 − Specialised firms. − Producers of high-tech goods. − Relatively large share of foreign capital. wyrobach potrzeb i gustów odbiorców zagranicznych 3 Suppliers of resources and raw materials: producers of machinery and equipment Dostawcy surowca i materiałów: producenci akcesoriów meblowych handlowe firm zagranicznych 2 − Relatively small share of large firms − A wide range of products offered − Lack of business support organisations and these dominated by the entities and many possibilities for their reinforcing these companies. with foreign capital. application. − Cooperation with the customers – both − Competitive sales representatives from − Products corresponding with the needs from the furniture industry and other foreign companies. and tastes of foreign customers. industries. − Nieliczne duże firmy, wśród nich − Szeroki asortyment produkowanych − Relatively limited activities focusing przewaga podmiotu z kapitałem wyrobów i duże możliwości ich on forming associations, despite the zagranicznym. zastosowań. relatively good potential conditions for − Konkurencyjne przedstawicielstwa − Uwzględnianie w produkowanych cooperation. Suppliers of resources and raw materials: producers of furniture accessories 1 Tabela 4. Ciąg dalszy Table 4. Continued 130 Milena Ratajczak-Mrozek, Magdalena Herbeć − High-tech firms. Usługodawcy: dostawcy oprogramowania (branża IT) − Firmy high-tech − Nowoczesne oprogramowanie mogące być wykorzystane na każdym etapie produkcji i zarządzania w meblarstwie − Szeroki zakres usług i poziom działań wpływający na innowacyjność procesów produkcji i zarządzania w meblarstwie − Niski poziom działań wśród mniejszych często krajowych podmiotów (brak przedstawicielstw w UE). − Wykorzystywanie przez duże firmy struktur sieciowych do świadczenia szerokiego zakresu usług (rozwinięte centra logistyczne) − Modern software which can be utilised − Broad range of services and activities at each stage of the production and influencing the innovativeness of management processes in the furniture production and management processes industry. in the furniture industry. i zautomatyzowania całości lub fragmentu świadczonych usług (np. − Duże zróżnicowanie podmiotów pod ułożenie ładunku w samochodzie). względem ich wielkości i jakości świadczonych usług (konkurencyjne duże firmy − Mało rozwinięta flota samochodowa mniejszych firm spedycyjnych świadczące kompleksowe usługi spedycyjne). − Udział kapitału zagranicznego, zwłaszcza w dużych firmach Service providers: software suppliers (IT industry) Usługodawcy: firmy transportowe, logistyczne − Rosnące znaczenie korzystania z tego rodzaju usług w meblarstwie − Growing importance of the use of this type of service in the furniture industry. 4 − Ability to mechanise and automate the − Low level of activity in the case of whole or part of the services provided small, often domestic firms (lack of an (e.g. loading vehicles). EU presence). − Less developed fleet among smaller − Use of network structures among firms transport firms. in order to provide a wide range of − Możliwość zmechanizowania services (developed logistics centers). − Large differentiation of entities in terms of their size and the quality of services provided (large competitive firms providing holistic logistics services). − Foreign capital is present especially in the case of large firms. z zakresu design Service providers: transport firms and logistics Usługodawcy: design − Przedsiębiorstwa świadczące usługi w oparciu o znajomość zmieniających się na rynku trendów; często wzorowanie się na doświadczeniu podmiotów międzynarodowych. − Powstawanie nowych podmiotów 3 − Firms providing services based upon − Specialised computer software knowledge of changing market trends; facilitating the provision of design often modelled on the experiences of services. − Wyspecjalizowane oprogramowanie international entities. umożliwiające świadczenie usług − Creation of new business entities. 2 Service providers: designers 1 Tabela 4. Ciąg dalszy Table 4. Continued Actors-resources-activities analysis as a basis for Polish furniture network research 131 3 − Wykwalifikowana kadra. − Rozwinięte zaplecze badawcze. − Wysoki poziom wiedzy. − Dostęp do międzynarodowego know-how − Obecność podmiotów w strukturach sieciowych w meblarstwie, czasami pełnienie roli koordynatora. − Relatywnie małe zainteresowanie firm meblarskich współpracą z tymi aktorami. − Coraz częstsza współpraca z ośrodkami międzynarodowymi − Presence of entities in the structures of furniture networks, sometimes in the role of coordinator. − Relatively limited interest among furniture firms to cooperate with these actors. − Increasing frequency of cooperation with international centres. − Aktywne uczestniczenie aktorów w strukturach sieciowych w meblarstwie, często nawet pełnienie roli koordynatora sieci. − Relatywnie małe zainteresowanie firm meblarskich współpracą z tymi aktorami (często wynikające z braku wiedzy o potencjalnych korzyściach) 4 − Relatively small capital resources. − Active participation among actors in − High level of market knowledge. network structures in the furniture industry. − Relatywnie małe zasoby kapitałowe. Often, actors are the coordinators of the − Wysoki poziom wiedzy rynkowej network. − Relatively limited interest among furniture firms to cooperate with these actors (often the result of limited knowledge regarding the benefits of such cooperation). − Qualified management. − Developed R&D capabilities. − Podmioty o wieloletniej tradycji i dużym − High level of knowledge. doświadczeniu − Access to international knowhow. − Very experienced entities with many years of tradition. − Podmioty często o regionalnym zakresie działania 2 − Entities which often operate at a regional level. Źródło: Opracowanie własne na podstawie [Figielek et al. 2001; Ratajczak et al. 2003; Ratajczak 2009; Ratajczak 2010; CSO 2013b] Source: Authors’ own work based upon [Figielek et al. 2001; Ratajczak et al. 2003; Ratajczak 2009; Ratajczak 2010; CSO 2013b] Pozostali: ośrodki badań i rozwoju, szkoły wyższe Others: R&D centres & institutions of higher education Pozostali: instytucje otoczenia biznesu, administracja państwowa Others: surrounding business environment and government institutions 1 Tabela 4. Ciąg dalszy Table 4. Continued 132 Milena Ratajczak-Mrozek, Magdalena Herbeć Actors-resources-activities analysis as a basis for Polish furniture network research 133 The specifics of resources and activities In addition to the information presented in table 4, it should be stressed that the basic resources which define the characteristics of the furniture industry are wood materials, of which this industry is a key recipient. Above all these are wood-based panels and sawnwood. These are mainly domestic raw materials (in 2012, 93% of the total demand for wood raw materials throughout the Polish economy was covered domestically [WTI estimates]). For this reason, the furniture industry is strongly dependent on the availability and prices of these wood resources, both directly as a recipient and also indirectly as an end-user of wood (sawnwood and wood-based panels). The reliance of the furniture industry on a natural resource means that there is limited potential for technical advances as well as mechanisation of the work. This natural resource is susceptible to a relatively simple form of processing which limits the potential for introducing modern technologies. However, conversely, the ecological characteristic of wood raw materials promotes the need for new processes and refined products [Ratajczak 2009]. Simultaneously, the relatively low R&D intensity is the reason why the furniture industry is a low-technology industry (a so-called traditional industry) [Hatzichronoglou 1997]. Another important resource used in the furniture industry is production machines. It is at this point worth noting the high-technology flow relationship directed at the furniture industry. It is estimated that the most modern production machinery and the highest level of technology is present in furniture produced for rooms, bedrooms, offices and kitchens especially in medium and large enterprises [Ratajczak 2009]. Computer software is also classified as high-technology and plays an important role in furniture firms. Not only can it improve production processes but it also creates the possibility of customising products as per individual customer requirements. This means that there is a drive towards limiting the activity of buffer stocks in favour of producing made-to-order furniture based upon technological lines. In effect, finished furniture components are generally prepared in machining centres and automatically fed in to computer controlled production lines [Ratajczak 2009]. Solutions delivered by the IT industry provide for a wide range of applications in the furniture industry both as a result of the utilisation of software by employees as well as through the relationships with external actors – logistical firms [Gackowska 2013]. Whilst analysing the resource interdependencies in the context of utilised resources, materials and software, it is possible to observe the nature of the activity interdependencies in the form of specificities of the production process. It should be underlined that the multistage furniture production process creates a basis for utilising outsourcing services which are popular on the market. The complex na- 134 Milena Ratajczak-Mrozek, Magdalena Herbeć ture of the furniture production process characterised by a large number of collaborators, complicated supply logistics and multifaceted relationships implies network links with the various actors presented in fig. 2 and table 4 which in turn influences the network structures operating in the industry. However, it has to be underlined that within the furniture industry network, resources are mainly created individually and then implemented by particular firms from the furniture industry. Generally, cooperation is based on long-term transactional exchange and adaptation of bought input resources and not on mutual adaptation or mutual creation of resources. The exemption may be the production of tailor-made products for individual customer orders requiring e.g. the development of new technical solutions or parts in collaboration with suppliers. Conducive conditions for joint activities are also present among the members of business support organisations, e.g. Centre for Innovation and Technology Transfer For the Furniture Industry in Poznan. Commercialisation of research results and technology transfer to industry involves the resources of many actors and contributes to joint operations. Both joint creation of resources and joint activities represent an important and desired direction in the development of the furniture industry. Moreover, an analysis of the activities undertaken by actors from the furniture industry points to the significant potential in terms of poorly-developed relationships, specifically in the case of the main actors within the furniture industry, when cooperating with actors from the surrounding business environment. The dominance of micro and small firms in the furniture industry in the entity structure of this industry should also encourage the more efficient utilisation of their ability to flexibly adapt to changes and as a result to diversify their operations. Conclusions The cooperation and network relationships between entities from the surrounding business environment in the case of the furniture industry can influence the stable development of individual firms as well as the industry as a whole. Relationships can generate a wide range of benefits which otherwise would remain unattainable for independently-operating, individual micro and small firms (these types of firms are dominant in the industry). The main contribution of the article is in highlighting the specific nature of the furniture industry from the perspective of the ARA model, and in particular in identifying the main entities within the industry, the surrounding business environment as well as their characteristics. The analysis is not limited solely to entities from a given industry so to include some significant factors influencing it – both in a positive and negative sense. This is especially important in the case of the industry at hand. In the opinion of specialists, furniture production is still characterised by a very limited degree of cooperation, including but not limited to R&D institutions which are the creators of innovation. Thus the analysis of Actors-resources-activities analysis as a basis for Polish furniture network research 135 the nature of resources and activities in the case of this industry, as well as their utilisation through cooperation with actors can significantly impact the stable development of the furniture industry. The analysis carried out within the article is not free of certain limitations which simultaneously lay the foundations for future research. 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PERSPEKTYWA MODELU ARA (AKTORZY-ZASOBY-DZIAŁANIA) Streszczenie Ważne korzyści otrzymywane dzięki współpracy i relacjom sieciowym są istotne zarówno z perspektywy samych przedsiębiorstw (z powodu chociażby poprawy wyników rynkowych), jak i konkretnych przemysłów czy całej gospodarki (poprawa konkurencyjności). Z tego powodu identyfikacja potencjału sieciowego na poziomie konkretnego przemysłu wraz z analizą jego specyfiki w ujęciu sieciowym jest również istotna dla wspierania więzi regulacyjnych dotyczących danej dziedziny gospodarki. W związku z powyższym celem artykułu jest identyfikacja specyfiki – ważnego dla polskiej gospodarki – przemysłu meblarskiego z wykorzystaniem podejścia sieciowego i dzięki temu wskazanie istotnych podmiotów, a także zależności w zakresie zasobów i działań, wywierających wpływ na ten przemysł. W prezentowanej analizie wykorzystano model ARA (Actors-Resources-Activities), który jest jednym z podstawowych modeli stosowanych do analizy zależności w podejściu sieciowym. W efekcie możliwe było wskazanie specyfiki omawianego przemysłu zgodnie z modelem ARA (w zakresie podmiotów, zasobów i działań), a w szczególności zidentyfikowanie głównych podmiotów przemysłu i otoczenia oraz ich charakterystyki. Jest to o tyle ważne, że ograniczanie analiz wyłącznie do podmiotów z danego przemysłu powoduje pominięcie istotnych czynników wywierających na niego wpływ – zarówno pozytywny, jak i negatywny. Dokonana analiza specyfiki przemysłu meblarskiego z wykorzystaniem modelu ARA stanowi pewien schemat koncepcyjny, który ma dać podstawę do przyszłych analiz z zakresu złożoności relacji poszczególnych przedsiębiorstw oraz całego przemysłu. Słowa kluczowe: sieć biznesowa, podejście sieciowe, relacje sieciowe, współpraca, model ARA, przemysł meblarski, otoczenie przemysłu meblarskiego Acknowledgements The paper was written with financial support from the Polish National Center of Science [Narodowe Centrum Nauki] – Decision no. DEC-2012/05/D/HS4/01138. Project „The global and local dimension of business networks” (project leader Milena Ratajczak-Mrozek, PhD). Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.039.09 DONIESIENIA NAUKOWE – RESEARCH REPORTS Jacek Wilkowski, Piotr Borysiuk, Jarosław Górski, Paweł Czarniak 2 ANALYSIS OF RELATIVE MACHINABILITY INDEXES OF WOOD PARTICLE BOARDS BONDED WITH WASTE THERMOPLASTICS The paper presents original data concerning one aspect of the machinability of special, wood particle boards bonded with waste thermoplastics. The study focused on the measurement of drilling torque and thrust force. The classic idea of machinability indexes was used. The experimental plastic particle boards (with a nominal density of 650 kg/m3) were made of industrial grade core-layer pine wood particles and three different waste thermoplastics: polyethylene, polypropylene and polystyrene. Three different proportions of plastic contents were used: 30, 50 and 70%. The machinability of the boards was tested in relation to commercially-produced materials: standard medium-density fibreboard (MDF) and standard particle board (with nominal densities: 750 and 650 kg/m3, respectively). Data presented in the paper suggest that the machinability of wood particle boards bonded with waste thermoplastics, especially waste polyethylene, is particularly good, not only in relation to standard particle boards, but even in relation to standard MDF. Keywords: wood-plastic composites, waste thermoplastics, machinability Jacek Wilkowski, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] Piotr Borysiuk, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] Jarosław Górski, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] Paweł Czarniak, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] 140 Jacek Wilkowski, Piotr Borysiuk, Jarosław Górski, Paweł Czarniak Introduction Nowadays, wood-plastic composites (WPC) are mass produced materials made of wood (fibres, flour, chips etc.) and, most popularly, of thermoplastics. It is generally known that the workability of WPC is reasonably good but there is a lack of quantitative data concerning their machinability indexes. Previous studies of WPC machinability [Buehlmann et al. 2001; Somsakova et al. 2012] are inadequate from this point of view. The paper presents original data concerning one aspect of the machinability of special, wood particle boards bonded with waste thermoplastics. The study focused on the measurement of drilling torque and thrust force. The classic idea of machinability indexes [Globocki et al. 2009] was used. The basic aim of the study was to analyze the machinability of wood particle boards bonded with waste thermoplastics in relation to commercially-produced materials: standard medium-density fibreboard (MDF) and standard particle board. Materials and methods The experimental plastic particle boards (with a nominal density of 650 kg/m3) were made of industrial grade core-layer pine wood particles and three different waste thermoplastics: polyethylene (PE), polypropylene (PP) and polystyrene (PS). The boards were made following the procedure developed by Borysiuk et al. [2008], and hence 16-mm thick boards were prepared. The pressing parameters were as follows: maximum unit pressure 2.5 MPa, temperature 200oC, pressing time 10 min. The boards were cooled under pressure for 15 min. Three different proportions of plastic contents were used: 30, 50 and 70%. Consequently, the machinability of nine variants of plastic particle boards was tested. The machinability of the boards was tested in relation to commercially-produced materials which were the objects of an earlier study [Podziewski, Górski 2011], standard medium-density fibreboard (MDF) and standard particle board (with nominal densities of 750 and 650 kg/m3 respectively). In all the cases, the drilling process was carried out by means of a standard CNC machine tool (Busellato JET 130) and a standard PCD drill (10mm, Leitz 91193). Three spindle speeds (3000, 6000 and 9000 rpm) and five values of feed per revolution (0.1; 0.15; 0.20; 0.25; 0.3 mm) were used. Consequently, fifteen variants of cutting parameters were taken into account. The basis of the machinability assessment was the monitoring of the drilling torque (M) and of the thrust force (F), therefore an adequate measuring system (Kistler 9345A, Kistler 5073A) and data acquisition system (NI PCI 6034E, NI LabVIEW) were used. Analysis of relative machinability indexes of wood particle boards bonded with waste thermoplastics 141 Adopting commercial MDF as the universal, reference wood-based material, two relative machinability indexes (MIM and MIF) were defined: MIM = (MMDF/Mi) (1) MIF = (FMDF/Fi) (2) where: MMDF, FMDF – mean values of drilling torque and thrust force observed when drilling in MDF (all of the fifteen variants of cutting parameters were taken into account); Mi, Fi – analogue values observed when drilling in the i-th material (i.e. the particular material tested for its machinability, which was then compared with the machinability of MDF). The experimental data related to the machinability indexes were analyzed by means of a special software package – STATISTICA 10 (StatSoft Inc.). The analysis was carried out using the standard method of variance analysis (multi-factor ANOVA). The general characteristics of MDF, as the reference material, were determined in experimental way according to the adequate standards. The basic properties of MDF were as follows: tensile strength [EN 319] – 0.57 MPa, bending strength [EN 310] – 40 MPa, modulus of elasticity [EN 310] – 4020 MPa, swelling in thickness after immersion in water [EN 317] – 8%. Results and discussion The values of the relative machinability indexes, based on the measurement of drilling torque and thrust force , are illustrated in fig. 1 and fig. 2, respectively. It should be noted that the values of both indexes proved to be relatively high for all the special plastic particle boards, especially in relation to the standard wood particle board. This is a very important fact since the lower the drilling torque, the lower the cutting power (i.e. lower energy costs). Moreover, the lower the thrust force, the lower the risk of drill buckling or breakage, which are common problems observed for small hole drilling, especially for high feed rates. From this point of view, the best of the tested materials were the wood particle boards bonded with polyethylene waste (PE). At any rate, the more polyethylene, the better the machinability (at least in the tested range of percentage content). The statistical significance (p-value below 0.01) of this conclusion was based on thestandard method of variance analysis (multi-factor ANOVA). The use of polypropylene (PP) or polystyrene (PS) as bonding components of the boards also had a positive, but much less spectacular effect. In this case, the increase in the plastic content from 30 to 70%, had no statistically significant effect on the machinability indexes. 142 Jacek Wilkowski, Piotr Borysiuk, Jarosław Górski, Paweł Czarniak Fig. 1. Values of relative machinability index based on measurement of drilling torque (MIM – machinability index defined in the text by means of formula 1, PE – polyethylene, PP – polypropylene, PS – polystyrene) Rys. 1. Wartości względnego wskaźnika skrawalności związanego z momentem obrotowym skrawania (MIM – wskaźnik skrawalności zdefiniowany w tekście za pomocą wzoru 1, PE – polietylen, PP – polipropylen, PS – polistyren) Fig. 2. Values of relative machinability index based on measurement of thrust force (MIF – machinability index defined in the text by means of Formula 2, PE – polyethylene, PP – polypropylene, PS – polystyrene) Rys. 2. Wartości względnego wskaźnika skrawalności związanego z siłą osiową (MIF – wskaźnik skrawalności zdefiniowany w tekście za pomocą wzoru 2, PE – polietylen, PP – polipropylen, PS – polistyren) Analysis of relative machinability indexes of wood particle boards bonded with waste thermoplastics 143 Conclusions The data presented above suggest that the machinability of wood particle boards bonded with waste thermoplastics, especially waste polyethylene, is particularly good not only in relation to standard particle boards, but even in relation to standard MDF. References Borysiuk P., Mamiński M., Nicewicz D., Boruszewski P., Zado A. [2008]: Waste thermoplastics as a binder for green and recycled wood bonding in particle board manufacturing. Proceedings of the International Panel Products Symposium, Dipoli Conference Centre, Espoo, Finland, 24–26 September: 249–254 Buehlmann U. Saloni D., Lemaster L.R. [2001]: Wood fiber-plastic composites: machining and surface quality. Proceedings of the 15th International Wood Machining Seminar, Anaheim, CA, July 30 – Aug 1 Globocki G., Borojevic S., Cida D. [2009]: Development of the application for analysis of machinability index. Tribology in industry 31 [1–2]: 57–60 Podziewski P., Górski J. [2011]: Relationship between machining conditions and feed force during drilling in some wood-based materials. Ann. WULS-SGGW, Forestry and Wood Technology [75]: 216–219 Somsakova Z., Zajac J., Michalik P., Kasina M. [2012]: Machining of Wood Plastic Composite (Pilot Experiment). Materiale Plastice 49 [1]: 55–57 List of standards EN 310 [1993]: Wood-based panels: Determination of modulus of elasticity in bending and of bending strength EN 317 [1993]: Particle boards and fibreboards: Determination of swelling in thickness after immersion in water EN 319 [1993]: Particle boards and fibreboards: Determination of tensile strength perpendicular to the plane of the board ANALIZA WZGLĘDNYCH WSKAŹNIKÓW SKRAWALNOŚCI PŁYT WIÓROWYCH SPAJANYCH TERMOPLASTAMI POUŻYTKOWYMI Streszczenie Kompozyty drewnopochodne określane jako WPC (wood-plastic composites) zawierają zwykle cząstki drewna (w formie wiórów, włókien, mączki) spojone za pomocą najpopularniejszych termoplastów. Ogólnie wiadomo, że obrabialność takich kompozytów jest 144 Jacek Wilkowski, Piotr Borysiuk, Jarosław Górski, Paweł Czarniak całkiem dobra, ale problemem jest brak jakichkolwiek danych ilościowych dotyczących ich wskaźników skrawalności. Wcześniejsze badania skrawalności WPC są całkowicie niewystarczające z tego punktu widzenia. Niniejszy artykuł prezentuje oryginalne dane na temat jednego z aspektów skrawalności specjalnych płyt wiórowych spajanych za pomocą termoplastów odpadowych. Badania koncentrowały się na pomiarze momentu obrotowego wiercenia i siły osiowej. Podczas interpretacji wyników wykorzystano klasyczną koncepcję wskaźników skrawalności względnej. Płyty eksperymentalne (o nominalnej gęstości 650 kg/m3) były wykonywane z przemysłowych, przeznaczanych na warstwę wewnętrzną, wiórów sosnowych oraz z trzech różnych termoplastów poużytkowych. Wykorzystywano przy tym trzy różne udziały procentowe tworzyw sztucznych: 30, 50 i 70%. W konsekwencji testowano skrawalność dziewięciu różnych wariantów płyt. Badano skrawalność tych płyt w odniesieniu do materiałów komercyjnych – standardowej płyty MDF oraz standardowej płyty wiórowej (o nominalnych gęstościach wynoszących odpowiednio: 750 i 650 kg/m3). Uzyskane dane eksperymentalne sugerują, że skrawalność płyt wiórowych spajanych termoplastami poużytkowymi (zwłaszcza polietylenem) jest naprawdę dobra nie tylko w odniesieniu do standardowych płyt wiórowych, ale nawet w odniesieniu do standardowej płyty MDF. Słowa kluczowe: kompozyty drewno-tworzywo sztuczne, termoplasty odpadowe, skrawalność Acknowledgements All the experiments presented in the paper were financed by the National Science Centre in Poland, grant No. N N309 007537 (“Machining of wood based materials” 2009-2013). Drewno 2013, vol. 56, nr 190 DOI: 10.12841/wood.1644-3985.048.10 Michał Aniszewski, Piotr Witomski3 THE STATE OF PRESERVATION OF ARCHAEOLOGICAL WOOD UNCOVERED IN THE GROTTO FOUNDATIONS OF THE RETAINING WALL OF THE PALACE MUSEUM IN WILANÓW The following paper presents the results of the examination of archaeological wood from excavations carried out in the gardens of Wilanów Palace. The main purpose of the research work was to determine its state of preservation. In order to accomplish this, chemical and physical examinations were carried out on wood samples taken from the level of the grotto foundations. Keywords: waterlogged archaeological wood, chemical analyses, physical analysis, European Spruce, archaeology, Wilanów Palace Introduction In the course of excavations, relics of material culture made from various species of wood are found at various types of archaeological sites. During archaeological work, architectural remains, elements of constructions, waterworks and plumbing systems, as well as minor objects such as vessels or ornaments, are unearthed. During underwater archaeological work, boatbuilding relics – dugout boats, stave boats and ships are discovered. The state of preservation of wooden relics depends more on the conditions in which they were kept until the moment of their discovery, than on the duration of their deposition in archaeological layers. The type of used wood and the conditions the objects were in have a considerable impact on their degradation. Of considerable significance for the speed and scale of decay of wood tissue is the type of environment and its pH value, oxygenation, moisture, temperature, the presence of microorganisms, and sometimes also seasonal changes in conMichał Aniszewski, National Heritage Board of Poland, Warsaw, Poland e-mail: [email protected] Piotr Witomski, Warsaw University of Life Sciences, Warsaw, Poland e-mail: [email protected] 146 Michał Aniszewski, Piotr Witomski ditions [Witomski 2009]. Wooden archaeological relics found in different types of wet natural environments are subjected to other degradation factors. The process of wood degradation proceeds more slowly under anaerobic conditions, occurring in swamps and peatbogs. Examination of the samples taken from the elements of the construction uncovered at the level of the foundations of the retaining wall of Wilanów Palace’s grotto allowed researchers to determine the state of preservation of the construction wood making up the elements of the retaining wall’s foundations. This was possible to achieve owing to the fact that the stratigraphy of the lower terrace of the residential garden was established, according to which all the wooden objects were located in the same cultural layers. Determining the wood species – spruce, which did not occur in the Mazovia Region when the retaining wall was constructed (17th c.) – suggests that it could have been brought from the south of Poland as construction material, an assumption corroborated by historical sources which refer to other construction materials used for the building of the retaining wall [Starzyński 1976]. In the year 2003, an archaeological survey commenced inside the garden complex, conducted by the National Centre for Historical Monument Studies and Documentation (currently the National Heritage Board of Poland). The need to conduct the excavations was prompted by the beginning of the renovation of Wilanów Palace and the revitalization of the gardens constituting an integral part of the palace complex. The goal of the archaeological research was to determine the location of the compositional elements of the garden – their form and scale at the different stages of the complex’s development. The retaining wall is already visible on a copy of the oldest plan of the King’s property, drawn by Adolph Boy in 1682 [Hanaka 2005]. The process of the wall’s construction is also described several times in the letters of architect Augustyn Locci to King Jan III Sobieski [Sikora 2005]. During the excavations, it was concluded that the wall had been erected in a surprisingly inexpert manner. This applies especially to the construction of the bow of the arcade foundations, of the joints between the different sections and the way the formwork was done. Material and methods The grotto foundations were built as an escarpment-based construction. The palace-garden complex is situated on the floodplain terrace of the Vistula River valley, which accounts for the high water table present in the area. The grotto foundations were embedded in narrow trenches, delving ca. 5.10–5.20 m n.p.w1. Wood samples for the examination of the state of preservation were obtained from construction element [622], unearthed at the level of the foundations, in trial pit 60. 1 Meters above Wilanow level. The state of preservation of archaeological wood uncovered in the grotto foundations ... 147 The function of the construction [622] is not clear. It consists of long piles of 120 cm in length, set at a 45o angle relative to the face of the wall, embedded beneath the footing of the foundations. Fig. 1. Work at the grotto foundations – South-East; a fragment of construction [622] is visible, trial pit 60. [photo Michał Aniszewski] Rys. 1. Prace przy fundamentach Groty – SE, widoczny fragment konstrukcji [622], sondaż 60. [fot. Michał Aniszewski] Undoubtedly, this construction appeared before the creation of the wall itself. It may have originally functioned as a formwork designed to protect the ditch from earth slides during the bricklaying. Driving a row of piles into the natural layers found beneath the construction level may have also served to demarcate the construction line, defining the position of the foundations and the eastern wall of the grotto. Wood samples for physical and chemical analysis were extracted from the construction element [622], excavated at the level of the foundations , in trial pit 60. After excavation and documentation work in the grotto’s retaining wall was concluded, one of the most easily extractable piles was obtained. It was moved to the Department of Wood Protection at Warsaw University of Life Sciences for laboratory analysis. A piece of ca. 50 cm in length was cut out, from which samples 148 Michał Aniszewski, Piotr Witomski for chemical and physical tests were prepared. The tests allowed researchers to determine the structural and non-structural substance content, hardness and shrinkage. The results and the subsequent analysis based on a comparison of the values obtained with other results and norms were to determine the state of wood preservation. In order to conduct the chemical analysis and to indicate the moisture content of the wood, the samples were mechanically fragmented and fractionated using a sieve. In order to conduct physical analysis, rectangular blocks of three different sizes were prepared. The study was conducted in the research laboratories of the Department of Wood Protection at Warsaw University of Life Sciences. The first analysis conducted was the determination of the species of wood used to assemble the construction [622]. The macroscopic characteristics of the material under examination were: a glossy surface, a bright yellow color, the absence of a tinged heartwood, as well as clearly visible growth rings and resin canals. These traits are characteristic of the wood of European Spruce (Picea abies (L.) H. Karst). For the botanical identification of the wood, samples with an average moisture content of 11.1% were used. The analysis of the structure of the wood was performed using three anatomical cross-sections: transverse, tangential and radial. The indication of the species was carried out on the basis of the analysis of the anatomical elements, observed under an Olympus BX41 microscope. Visible in the microscopic image of the transverse cross-section were tracheids arranged in regular rows, as well as longitudinal resin canals, their epithelial cells made of thick, ligneous walls. No medullary rays were observed. In the tangential cross-section, transverse resin canals were visible, surrounded by heterogeneous, single row, fusiform medullary rays. In the radial cross-section, 1–4 simple cross-field pits were noted, as well as longitudinal tracheids, distributed in radial rows, while the thickness of the walls of the cells increased towards the growth limit. Visible on the radial walls of the tracheids were infundibuliform cavities arranged in a single row. The microscopic images unambiguously confirmed the assumption based on the macroscopic characteristics of the material, that the samples extracted from the construction element [622] were in fact European Spruce wood (Picea abies (L.) H. Karst). The identification of the wood species (spruce) which did not occur in the Mazovia Region in the 17th century, may suggest that it was brought from the south of Poland, together with other construction materials used for the building of the retaining wall – information concerning the importing of construction materials can be found in written sources [Starzyński 1976]. The examination of the state of preservation of the wood was conducted using the following test procedures: 1. Determination of the basic technical parameters of the wood was conducted for: The state of preservation of archaeological wood uncovered in the grotto foundations ... 149 –– the absolute moisture content: this was determined through the oven-dry method on dried samples (12 samples measuring 20 × 20 × 20 mm); –– the density of the wood: this was determined using the stereometric method according to the procedure of the PN-77/D-04101 [1997] standard (12 samples); –– linear shrinkage in the radial and tangential directions: this was determined on the basis of the methodology of the PN- 82/D-04111 [1982] standard (6 samples measuring ca. 30 × 30 mm and a thickness of 5 mm); –– the examination of the resistance of the compressive strength along the fibers: this was performed in accordance with the procedure of the PN-79/D-04102 [1979] standard (12 samples measuring 30 × 20 × 20 mm); –– the measurement of the hardness of the wood using the Brinell method: this was carried out with the use of Brinell’s hardness tester within the range of a 60 daN load (12 samples measuring 30 × 20 × 20 mm); 2. The chemical analyses were carried out for: –– the determination of non-structural substance content: this was carried out in the process of extraction in the Soxhlet apparatus using a chloroform and ethanol mixture [chloroform-ethanol (93:7)v]. The percentage of extractive substance content was calculated on the basis of the ratio of the extract mass to dry sawdust (3 samples); –– the determination of cellulose content in the wood: this was performed using the Kürschner-Hoffer method [Krutul 1994] (3 samples); –– the lignin content in the studied samples: this was determined according to the methodology of the Polish PN-74/P50092 standard (3 samples); –– the determination of the content of the substances soluble in the analyzed wood: this was performed with the use of 1% sodium hydroxide [Krutul 1994] (3 samples); –– the determination of alpha-cellulose content: this was carried out using the gravimetric method [Krutul 1994] on the cellulose mass obtained earlier using the Kürschner-Hoffer method (3 samples); –– holocellulose content: this was determined according to the methodology described by Krutul [1994] (3 samples); The values obtained were subsequently compared with test results for modern wood, available in written sources. The indication of the state of preservation of historic wood determines the proper method for any future conservation. 150 Michał Aniszewski, Piotr Witomski Results and discussion Table 1. Physical properties of archaeological wood from Wilanów and modern European Spruce wood (Picea abies (L.) H. Karst) Tabela 1. Cechy fizyczne archeologicznego drewna z Wilanowa oraz współczesnego drewna świerka pospolitego (Picea abies) (L.) H. Karst) European Spruce Wood (Picea abies) (L.) H. Karst) Drewno świerka pospolitego (Picea abies) (L.) H. Karst) Physical properties of wood Cechy fizyczne drewna Density of wet wood Gęstość drewna mokrego Density of dry wood Absolute moisture content Wilgotność bezwzgledna Skurcz liniowy w kierunku promieniowym [%] Linear shrinkage in the tangential direction Skurcz liniowy w kierunku stycznym Compressive strength Wytrzymałość na ściskanie wzdłuż włókien Brinell’s hardness Twardość Brinella Drewno archeologiczne Modern wood according to Krzysik [1974] Drewno współczesne Krzysik [1974] Change in relation to modern wood Zmiana w odniesieniu do drewna współczesnego [%] 920 – – 421 330−470−680 –10.4 146 157 −7 2.99 3.6 −16.9 6.22 7.8 −20.3 37.5 30−43−67 −13 39.7 32 +26.8 [kg/m3] Gęstość drewna suchego Linear shrinkage in the radial direction Archaeological wood [MPa] The test results shown in the tables for the various parameters of the wood under examination did not diverge substantially from the values determined for modern wood. The density of the archaeological spruce wood differed from the average density of modern spruce by 14%, although it was still within the range of values considered “normal” for this species of wood. An improvement in certain parameters was even noted, namely the decrease in the absolute moisture of the wood by 7% compared to modern wood, as well as a decrease in the linear shrinkage by 17–20%. The resistance to compressive strength decreased by 13%, while Brinell’s hardness increased by 27%. The state of preservation of archaeological wood uncovered in the grotto foundations ... 151 Table 2. Average structural and non-structural substance content [%] in archaeological wood from Wilanów and in modern European Spruce Wood (Picea abies) (L.) H. Karst) Tabela 2. Średni [%] udział substancji strukturalnych i niestrukturalnych w drewnie archeologicznym z Wilanowa oraz we współczesnym drewnie świerka pospolitego (Picea abies) (L.) H. Karst) European Spruce Wood (Picea abies) (L.) H. Karst) Drewno świerka pospolitego (Picea abies) (L.) H. Karst) Structural and non-structural substances substancje strukturalne i niestrukturalne Archaeological wood Drewno archeologiczne Modern Wood according to Prosiński [1969] Współczesne drewno Prosiński [1969] Changes in relation to modern wood Zmiany w odniesieniu do drewna współczesnego [%] Content Zawartość [%] Cellulose Celuloza Alpha-cellulose (portion in cellulose) Alfaceluloza (zawartość w celulozie) Lignin Lignina 1% NaOH Soluble substances Substancje rozpuszczalne w 1% NaOH Holocellulose Holoceluloza Non-structural substances (extractives) Substancje niestrukturalne (ekstrakcyjne) 50.6 61.47 –18 73.7 – – 31.6 28.85 +9 9.3 11.65 –20 74.2 – – 4.6 3.06 +50 The 18% decrease in the cellulose content and in 1% NaOH soluble substances – small molecule sugars with a simultaneous retention of a good quality of cellulose (a high alpha-cellulose content) was indicative of only slight degradation processes in the wood, caused, under anaerobic conditions, mainly by chemical factors. The increase in the lignin content should be explained by its lack of decay. The increase in the content of extractives may be the effect of the accumulation of various types of deposits, typical for archaeological wood. Physical and chemical analysis of the material samples taken from the construction element [622] indicated a good state of preservation of the object dating, based on archaeological study and written sources, to the late 17th century. 152 Michał Aniszewski, Piotr Witomski The parameters of the archaeological spruce wood, dated as 300 years old, were close to the values characteristic for modern material of this species. This was the result of the deposition of the wood in anaerobic layers which preserved it from degradation agents. The grotto foundations, with the creation of which the pole construction [622] is undoubtedly connected, are partly dug into the natural geological strata of an argillaceous structure with decaying plant elements. The spruce piles were driven in beneath the foundation footing; they were found beneath the water table level, a fact which caused additional protection for the archaeological wood. Conclusions 1. The state of preservation of archaeological wood, discovered during archaeological fieldwork conducted in the grotto of the retaining wall of the palace-and-park complex at Wilanów, was determined. 2. A slight degradation of the archaeological wood in anaerobic layers was found. 3. The structural and non-structural substance content was similar to that of modern wood. 4. Construction elements [622] were subjected to slow hydrolysis which did not significantly influence the percentage of structural and non-structural substances in the wood tissue. 5. A decrease in the content of aliphatic compounds (ca. 18% of cellulose and ca. 20 % of hemicellulose) was found in comparison with modern wood. 6. The technical parameters of the archaeological wood were close to the values for modern spruce wood. 7. Resistance to the compressive strength of the examined wood was only 13% lower than that of modern wood. 8. Anaerobic layers had a „conservational” effect on archaeological wood. References Hanaka A. [2005]: Dwa przedstawienia muru oporowego w Ogrodzie Wilanowskim na obrazach Bernarda Bellotta, Monument, Warszawa Krutul D. [1994]: Ćwiczenia z chemii drewna oraz wybranych zagadnień chemii organicznej, Wydawnictwo SGGW, Warszawa Krzysik F. [1974]: Nauka o drewnie, PWN, Warszawa Prosiński S. [1969]: Chemia drewna, PWRiL, Warszawa Sikora D. [2005]: Mur oporowy w Ogrodzie Wilanowskim, Monument, Warszawa Starzyński J. [1976]: Wilanów, Dzieje budowy pałacu za Jana III, Warszawa Witomski P. [2009]: Czynniki powodujące rozkład drewna archeologicznego, w Stan i perspektywy zachowania drewna biskupińskiego, Biskupin: 77–97 The state of preservation of archaeological wood uncovered in the grotto foundations ... 153 List of standards PN-74/P50092 [1974]: Oznaczenie zawartości ligniny PN-77/D-04101 [1977]: Drewno. Oznaczanie gęstości PN-79/D-04102 [1979]: Drewno. Oznaczanie wytrzymałości na ściskanie wzdłuż włókien PN-82/D-04111 [1982]: Drewno. Oznaczania skurczu i spęcznienia STAN ZACHOWANIA DREWNA ARCHEOLOGICZNEGO ODKRYTEGO PRZY FUNDAMENTACH GROTY MURU OPOROWEGO PAŁACU W WILANOWIE Streszczenie W niniejszym opracowaniu przedstawiono wyniki badań drewna archeologicznego, pochodzącego z wykopalisk prowadzonych na terenie ogrodu Pałacu w Wilanowie. Głównym zamierzeniem pracy było określenie jego stanu zachowania. W tym celu przeprowadzono badania chemiczne i fizyczne próbek, które pobrano z fragmentu konstrukcji odkrytej na poziomie fundamentów Groty. Otrzymane wartości porównano z wynikami badań drewna współczesnego, dostępnymi w literaturze. Określenie stanu zachowania zabytkowego drewna determinuje odpowiednią metodę ewentualnej konserwacji. Próbki drewna do badań chemicznych i fizycznych pobrano z elementu konstrukcji [622], odkrytej na poziomie fundamentów, w sondażu 60. Funkcja konstrukcji [622] nie jest jednoznacznie określona. Jej elementami są pale o długości około 120 cm, ustawione pod kątem około 45o względem lica muru, wbite poniżej stopy fundamentu. Po zakończeniu prac wykopaliskowych i dokumentacyjnych w Grocie muru oporowego wydobyto jeden z najłatwiej dostępnych pali. Określenie gatunku drewna – świerka, nie występującego w owym czasie (w XVII w.) na Mazowszu – sugeruje, że jako materiał konstrukcyjny mógł on być sprowadzony z południa Polski, co znajduje potwierdzenie w źródłach historycznych w odniesieniu do innych materiałów budowlanych użytych do konstrukcji muru oporowego. Badania chemiczne i fizyczne próbek materiału pobranego z elementu konstrukcji [622] wskazują na dobry stan zachowania obiektu datowanego na podstawie badań archeologicznych i tekstów źródłowych na koniec XVII wieku. Parametry zabytkowego, archeologicznego drewna świerka, liczącego około 300 lat, są zbliżone do wartości charakterystycznych dla współczesnego surowca tego gatunku. Jest to wynikiem zalegania drewna w warstwach beztlenowych, które zabezpieczyły je przed czynnikami degradacji. Fundament Groty, z budową którego niewątpliwie związana jest konstrukcja palowa [622], jest częściowo wkopany w naturalne warstwy geologiczne o gliniastej strukturze z elementami gnijących roślin. Świerkowe pale wbito poniżej stopy fundamentu, znajdują się one poniżej poziomu wód gruntowych, co stanowiło dodatkowe zabezpieczenie dla zabytkowego drewna. 154 Michał Aniszewski, Piotr Witomski Słowa kluczowe: mokre drewno archeologiczne, badania chemiczne, badania fizyczne, świek europejski, archeologia, Pałac w Wilanowie Acknowledgements The authors would like to cordially thank Dr Paweł Kozakiewicz and Dr Michał Drożdżek for their professional advice and assistance during research.