Utilisation Potential and Market Opportunities for Plantation

Transcription

Queensland the Smart State
PN05.2022 Utilisation Potential
and Market Opportunities for
Plantation Hardwood Thinnings
from Queensland and Northern
New South Wales
June 2006
R.L. McGavin, M.P. Davies, J. Macgregor-Skinner,
H. Bailleres, M. Armstrong, W.J. Atyeo and J. Norton
The Department of Primary Industries and Fisheries (DPI&F) seeks to maximise the economic
potential of Queensland’s primary industries on a sustainable basis.
While every care has been taken in preparing this publication, the
State of Queensland accepts no responsibility for decisions or
actions taken as a result of any data, information, statement or
advice, expressed or implied, contained in this report.
© The State of Queensland, Department of Primary Industries and Fisheries 2006
Copyright protects this publication. The State of Queensland has no
objection to this material being reproduced but asserts its right to be
recognised as author of its original material and the right to have its
material remain unaltered.
PN05.2002 Utilisation Potential and Market Opportunities for Plantation Hardwood Thinnings from
Queensland and Northern New South Wales
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Acknowledgements
The project team would like to take this opportunity to acknowledge the wide range of
organisations and individuals that contributed to the success of this study.
From the forest and timber industries, the following are recognised for their substantial and
extremely valuable contributions to the project:
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Allied Timber Products – Richard Galley, Colin Galley and the sawmill and office staff;
Forest Enterprises Australia – Tony Cannon, Mike O’Shea, Geoff Pask, Randal Jacobson and
the sawmill staff;
Richards Sawmilling – Greg Richards, Warren Harvey and Cyril Richards and the sawmill staff;
Hurfords Family Group of Companies – Lexie Hurford, Andrew Hurford, Geoff Tongue and the
team at the truss manufacturing plant;
Palletmaster – Kevin Jackson and Daryl Clarke;
Ausgum Furniture – Chris Pilgram;
Perma-Log – Warren Jeffrey;
Big River Timbers – Stuart Austin and the processing and manufacturing team;
Hyne and Son – Jamin Tietz, Geoff Schwabe, Grant Muller and the Maryborough
Hynebeam/Edgebeam LGL plant; and
Australian Hardboards Ltd – Mr Kerry Trenaman and the team.
To the members of the various government organisations who provided valuable support and input
into the project:
• Queensland Department of Primary Industries and Fisheries – Mark Lewty and Mike Shaw;
• Forest New South Wales – Peter Paunovic, Nick Westman and Rob Heathcote (former
employee);
• New South Wales North Coast Institute of TAFE – Martin Tomasoni and the various students
and support staff; and
• Forest Plantations Queensland (formerly Department of Primary Industries - Forestry) – Ian
Robb.
The considerable inputs by the following researchers are also greatly appreciated:
• Michael Kennedy, Queensland Department of Primary Industries and Fisheries;
• John Huth, Queensland Department of Primary Industries and Fisheries;
• Geoff Dickinson, Queensland Department of Primary Industries and Fisheries;
• Mila Bristow, Southern Cross University;
• William Leggate, Queensland Department of Primary Industries and Fisheries; (former
employee);
• Eric Littee, Queensland Department of Primary Industries and Fisheries;
• Gary Hopewell, Queensland Department of Primary Industries and Fisheries;
• Terry Copley, Queensland Department of Primary Industries and Fisheries;
• Rodney Vella, Queensland Department of Primary Industries and Fisheries; and
• Adam Redman, Department of Primary Industries and Fisheries.
Special thanks goes to Errol Wiles for providing the red mahogany logs.
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The financial assistance provided by the Forest and Wood Products Research and Development
Corporation (FWPRDC) is gratefully appreciated as is the support provided by the FWPRDC staff
and in particular Chris Lafferty.
The support provided by the Queensland Department of Primary Industries and Fisheries through
the provision of the infrastructure and equipment at the Salisbury Research Centre is acknowledged
as critical to facilitate much of the testing necessary to complete studies of this nature.
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Contributors
Mr Robert L. McGavin
Research Scientist /Facility Manager
Salisbury Research Centre
Queensland Department of Primary Industries and Fisheries
50 Evans Road
Salisbury Qld 4017
Mr Martin P. Davies
Technician
50 Evans Road
Salisbury Qld 4017
Mr John Macgregor-Skinner
Project Manager/Executive Officer
Northern Rivers Private Forestry Development Committee
PO Box 823
Murwillumbah NSW 2484
Mr Henri Bailleres
Senior Principal Scientist (Product Development)
Indooroopilly Science Centre
80 Meiers Road
Indooroopilly Qld 4068
Mr Matthew Armstrong
Research Scientist
80 Meiers Road
Mr William J. Atyeo
Research Scientist
50 Evans Road
Salisbury Qld 4017
Mr Jack Norton
Senior Principal Scientist (Product Performance)
80 Meiers Road
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Executive Summary
Significant investment is being made in the establishment of hardwood plantations in Queensland
and northern New South Wales. While many plantation areas have been established with a pulp
market in mind, plantation managers may shift management strategy if more profitable product
options can be demonstrated.
Although it is anticipated that clear fall logs harvested at full rotation ages of 20 or 25 years will
produce saw and veneer logs of reasonable quality and size, economical processing options and
markets for thinnings material have not been established.
The aim of this study was to evaluate processing and utilisation options for thinnings sourced from
sub-tropical and tropical eucalypt plantations, by determining critical wood properties and wood
quality information through empirical trials. Additionally, thinnings material was provided to a
range of industry collaborators in order for them to assess the material for processing characteristics
and product performance.
Representative thinning populations of three species from various sub-tropical plantations were
harvested to provide the test specimens. Species selection was limited to availability of suitablyaged forests of desirable timbers, hence the trials were undertaken with:
• 8-year-old Gympie messmate (Eucalyptus cloeziana);
• 9-year-old blackbutt (E. pilularis); and
• 8.5-year-old red mahogany (E. pellita).
Laboratory tests were conducted to determine a range of physical, mechanical (sawn, composite and
round timber) and basic chemical characteristics. Industry participants prepared plywood,
hardboard, finger-joints, glued laminated beams, outdoor furniture components, roof trusses and
landscaping rounds as well as processed logs through specialised small log sawmills.
The wood properties’ data showed that wood from plantation thinnings is lower in strength,
hardness and density when compared with mature native forest wood of the same species. The
shrinkage and stability results for the plantation-grown wood were also lower and may indicate an
advantage over mature native forest wood. The thinnings logs contained higher proportions of
sapwood than found in mature native forest logs, which may be beneficial to products such as
treated round wood. These findings are consistent with earlier investigations on plantation grown
wood.
Natural round products provide some strength advantages over sawn timber and with further design
input to aesthetic structures and jointing methods, and improvements in seasoning techniques, could
provide a practical end-use for thinnings. In-grade testing results of structural solid wood revealed
that higher recoveries of graded material could be achieved than indicated by visual grading for
structural products. Current standards for visual grading for structural purposes do not appear to be
suitable for thinnings material. The proportional volume of knots and heart-related defects does
affect the overall recovery of sawn structural products.
The plywood manufactured during the trials provided a satisfactory product from strength and glue
bond perspectives. Similarly, results from tests conducted on the finger-jointed samples comply
with the relevant industry standard. Laminated beams passed testing protocols for strength and glue
bonding. Hardboard was manufactured successfully though standard production systems. Green,
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sawn recoveries through both HewSaw and Vislanda processing lines were equivalent to standard
hardwood industry expectations; however graded recovery was affected, primarily by the frequency
of knots.
Further work on areas such as solid wood grading and sorting systems, determining natural
durability characteristics and resource mapping is recommended, as is product exploration and
development in areas such as bio-energy, composites, alternative panel products, engineered wood
products and pulping.
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Table of Contents
Acknowledgements..............................................................................................................................3
Contributors .........................................................................................................................................5
Executive Summary .............................................................................................................................6
Table of Contents .................................................................................................................................8
List of Figures ......................................................................................................................................9
List of Tables .....................................................................................................................................10
List of Plates ......................................................................................................................................11
1. Introduction................................................................................................................................12
1.1
Objectives of the Study ......................................................................................................12
1.2
Layout of the Report ..........................................................................................................13
2
Issues with Industry Utilisation of Hardwood Plantation Thinnings.........................................14
3
Wood Material and Methodology ..............................................................................................15
3.1
Resource Selection.............................................................................................................15
3.1.1
Gympie Messmate (Eucalyptus cloeziana)................................................................15
3.1.2
Blackbutt (Eucalyptus pilularis) ................................................................................18
3.1.3
Red Mahogany (Eucalyptus pellita) ..........................................................................20
3.2
Data Analysis: Box Plot.....................................................................................................22
3.3
Small Clear Wood Properties.............................................................................................23
3.3.1
Basic Density .............................................................................................................23
3.3.2
Heartwood /Sapwood Proportions .............................................................................23
3.3.3
Extractives Content ....................................................................................................24
3.3.4
Hardness.....................................................................................................................24
3.3.5
Shrinkage and Unit Shrinkage ...................................................................................25
3.3.6
Strength Testing .........................................................................................................25
3.4
Full Section Characteristics and Properties .......................................................................26
3.4.1
3.4.2
Visual Grading –Structural ........................................................................................26
3.4.3
Round Wood Strength Testing...................................................................................27
3.4.4
Plywood Testing ........................................................................................................28
3.4.5
Glued Laminated Beam Testing ................................................................................28
4
Results and Discussion ..............................................................................................................30
4.1
Small Clear Wood Properties.............................................................................................30
4.1.1
Basic Density .............................................................................................................30
4.1.1.1 Within species variation.........................................................................................30
4.1.1.2 Comparison between the species of the study .......................................................32
4.1.1.3 Comparison with other eucalypts...........................................................................32
4.1.2
Heartwood /Sapwood Proportions .............................................................................33
4.1.3
Extractive Content......................................................................................................34
4.1.4
Hardness.....................................................................................................................35
4.1.5
Shrinkage and Unit Shrinkage ...................................................................................36
4.1.6
4.2
Full Section Characteristics and Properties .......................................................................40
4.2.1
Sawn Strength ............................................................................................................40
4.2.2
Visual Grading - Structural ........................................................................................44
4.2.2.1 Gympie messmate ..................................................................................................44
4.2.2.2 Blackbutt ................................................................................................................47
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4.2.2.3 Red mahogany........................................................................................................50
4.2.2.4 Visual grading discussion ......................................................................................53
4.2.3
Round Wood Strength Testing (Red Mahogany) ......................................................53
4.2.4
Plywood Testing ........................................................................................................54
4.2.5
Laminated Products....................................................................................................55
4.2.5.1 Finger-jointed scantlings........................................................................................55
4.2.5.2 Glued laminated beam testing................................................................................56
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Conclusions on the Properties and Characteristics ....................................................................58
5.1
Clear Wood Properties .......................................................................................................58
5.2
Full Section Properties .......................................................................................................58
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Product Opportunities ................................................................................................................60
6.1
Sawn Timber ......................................................................................................................60
6.2
Round Wood ......................................................................................................................61
6.3
Engineered Wood Products................................................................................................62
6.3.1
Veneer ........................................................................................................................63
6.3.2
Hardboard...................................................................................................................63
6.3.3
Medium Density Fibre Board (MDF) ........................................................................63
6.3.4
Particleboard ..............................................................................................................64
6.3.5
Strand Products ..........................................................................................................64
6.4
Pulp ....................................................................................................................................64
6.5
Wood Plastic Composites ..................................................................................................64
6.6
Bio-energy..........................................................................................................................64
Case Study 1: Forest Enterprises Australia – Launceston, Tasmania................................................66
Case Study 2: Richards Milling Company – Rappville, New South Wales ......................................68
Case Study 3: Hurford Family Group of Companies.........................................................................70
Case Study 4: Palletmaster – Clontarf, Queensland ..........................................................................72
Case Study 5: Ausgum Furniture – Gympie, Queensland .................................................................74
Case study 6: North Coast Institute of TAFE – Coffs Harbour, New South Wales ..........................76
Case Study 7: Perma-Log – Narangba, Queensland ..........................................................................78
Case Study 8: Big River Timbers – Grafton, New South Wales .......................................................80
Case Study 9: Hyne and Son – Maryborough, Queensland...............................................................82
Case Study 10: Australian Hardboards Limited – Bundamba, Queensland .....................................84
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Conclusion and Recommendations............................................................................................87
List of References ..............................................................................................................................89
List of Figures
Figure 1 Allocation of Gympie messmate for evaluation. .................................................................17
Figure 2 Allocation of blackbutt for evaluation.................................................................................19
Figure 3 Allocation of red mahogany for evaluation.........................................................................21
Figure 4 Within tree variation of basic density for Gympie messmate ............................................30
Figure 5 Within tree variation of basic density for blackbutt ............................................................31
Figure 6 Within tree variation of basic density for red mahogany ....................................................31
Figure 7 Intra and inter species variation of basic density for the three species of the study............32
Figure 8 Heartwood proportion in the three species assessed ...........................................................33
Figure 9 Sapwood thickness in the three species assessed ................................................................34
Figure 10 Average transverse Janka hardness (kN) in the three species assessed.............................35
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Figure 11 Radial and tangential percentage shrinkage shrinkage from green to 12 % moisture
content................................................................................................................................................36
Figure 12 Unit percentage shrinkage calculated from 12% to 5 % moisture content........................37
Figure 13 Total percent shrinkage from green to 12 % moisture content..........................................38
Figure 14 Small clear wood bending MOE in GPa ...........................................................................39
Figure 15 Small clear wood bending MOR in MPa...........................................................................39
Figure 16 Full section wood bending MOE in GPa...........................................................................41
Figure 17 Full section wood bending MOR in MPa..........................................................................41
Figure 18 Gympie messmate full section F-grade distribution (extrapolated from full section
strength testing)..................................................................................................................................43
Figure 19 Blackbutt full section F-grade distribution (extrapolated from full section strength testing)
............................................................................................................................................................43
Figure 20 Red mahogany full section F-grade distribution (extrapolated from full section strength
testing)................................................................................................................................................44
Figure 21 Grade recovery of Gympie messmate boards in accordance with AS2082:2000..............44
Figure 22 Primary reasons for Structural Grade 2 (F14) Gympie messmate boards failing to meet a
higher grade........................................................................................................................................45
higher grade........................................................................................................................................45
higher grade........................................................................................................................................46
Figure 25 Primary reasons for reject Gympie messmate boards failing to meet a higher grade. ......46
Figure 26 Grade recovery of blackbutt boards in accordance with AS2082:2000.............................47
Figure 27 Primary reasons for Structural Grade 2 (F11) blackbutt boards failing to meet a higher
grade...................................................................................................................................................48
grade...................................................................................................................................................48
grade...................................................................................................................................................49
Figure 30 Primary reasons for reject blackbutt boards failing to meet a higher grade. .....................49
Figure 31 Grade recovery of red mahogany boards in accordance with AS2082:2000.....................50
Figure 32 Primary reasons for Structural Grade 2 (F17) red mahogany boards failing to meet a
higher grade quality. ..........................................................................................................................51
Figure 35 Primary reasons for reject red mahogany boards failing to meet a higher grade quality. .52
List of Tables
Table 1 Tree measurements of a subset of selected 8-year-old Gympie messmate trees ..................16
Table 2 Log dimensions of a random sample of 9-year-old blackbutt logs.......................................18
Table 3 Number of red mahogany logs and volumes for each log allocation ...................................20
Table 4 Harvested 8.5-year-old red mahogany logs and origin of test pieces ...................................22
Table 5 Strength group ratings for seasoned timber (AS/NZS 2878:2000).......................................26
Table 6 Stress grade (F-grade) determination for seasoned timber (AS2082:2000) .........................27
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Table 7 Relationship between strength groups and F-grades for round wood (AS1720.1:1997) and
corresponding classification values (AS/NZS2878:2000).................................................................27
Table 8 Characteristic strengths, Modulus of Elasticity and Rigidity for horizontally laminated
glulam grades (AS1720.1:1997) ........................................................................................................29
Table 9 Percentage of weight loss after dichloromethane and water extraction for Gympie messmate
............................................................................................................................................................34
Table 10 Percentage of weight loss after dichloromethane and water extraction for blackbutt ........34
Table 11 Percentage of weight loss after dichloromethane and water extraction for red mahogany 34
Table 12 Shrinkage properties for mature wood of native forest species (extracted from Kynaston
et al 1994). .........................................................................................................................................38
Table 13 Seasoned MOE and MOR properties for native stand species (extracted from Bootle
2005). .................................................................................................................................................40
Table 14 Full section strength test summary for Gympie messmate ................................................42
Table 15 Full section strength test summary for blackbutt...............................................................42
Table 16 Full section strength test summary for red mahogany .......................................................42
Table 17 Number of Gympie messmate boards excluded due to distortion and end-splits..............47
Table 18 Number of blackbutt boards excluded due to distortion and end-splits.............................50
Table 19 Number of red mahogany boards excluded due to distortion and end-splits.....................53
Table 20 Strength test results for red mahogany poles .....................................................................53
Table 21 Plantation round wood strength data..................................................................................54
Table 22 Modulus of Elasticity and Rupture (parallel to the grain) in red mahogany plywood
samples...............................................................................................................................................54
Table 23 ‘B’ type glue bond test results (melamine-urea-formaldehyde) for red mahogany plywood
............................................................................................................................................................54
Table 24 Finger-joint bending results for Gympie messmate samples.............................................55
Table 25 MOE and MOR results for the Gympie messmate glued laminated beams ......................56
Table 26 Summary of MOE and MOR results for the Gympie messmate glued laminated beams .56
Table 27 Glue joint cleavage test results ..........................................................................................56
Table 28 Finger-joint bending test results ........................................................................................56
Table 29 Cleavage test results from Gympie messmate glued laminated beams .............................57
Table 30 Volume of logs in corresponding diameter classes............................................................67
Table 31 Sawn dimensions and recovery..........................................................................................67
Table 32 Distribution of chip size.....................................................................................................84
Table 33 Results of the physical and mechanical tests of blackbutt hardboard................................85
List of Plates
Plate 1 HewSaw log processing line, EcoAshtm finished product and sawn project timber..............67
Plate 2 Vislanda log processing line, Richards Milling Company, Rappville, New South Wales ....69
Plate 3 Finished pallet product, stock piled feedstock and board quality .........................................73
Plate 4 Individual chair components and demonstration chair manufactured from plantation
thinnings.............................................................................................................................................75
Plate 5 Example of furniture designed and manufactured by students using timber from plantation
thinnings.............................................................................................................................................77
Plate 6 Splitting in round wood products presents a challenge to utilising hardwood thinnings .....79
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1. Introduction
There has been significant investment in hardwood plantations in Queensland and New South
Wales with the plantation area now an estimated 34,427 and 54,060 hectares respectively in these
two states (Parsons and Gavran 2005). For those plantations destined for solid wood products at
clearfalling, there will be a significant volume of thinnings logs produced at various stages of the
rotation. It is important to note that even though a significant percentage of Queensland’s hardwood
plantations are being managed for pulp markets, plantation managers may shift current management
practices towards solid wood regimes, if more profitable options can be demonstrated. Furthermore,
clear fall harvests for sawlogs at later ages will also yield a considerable volume of smaller logs
from the top of the trees with product prospects probably similar to thinnings.
Currently, there are no clearly identified viable markets for young (<15-year-old) hardwood
thinnings from plantations in Queensland and northern New South Wales. The main reason for this
is the general absence of reliable information on the suitability of the thinnings for various products
and concerns over the economic feasibility of utilisation (low value products and high harvesting
costs). Pulpwood is only currently regarded as a viable option for the thinnings if it is part of an
integrated operation with the harvest of other products and/or the plantation is within a 100
kilometre radius of a port or pulp mill (Heathcote 2004). Furthermore, existing processors and
manufacturers working with traditional resources such as plantation softwood or native forest
hardwood, have a general lack of awareness of the characteristics of the plantation hardwood
thinnings in terms of available volumes, location, species, log sizes, wood quality and suitability for
various products.
The economic viability of hardwood sawlog plantations depends upon a suitable thinning regime
and a commercial outcome from the material generated. Late thinning or no thinning can reduce the
potential of plantations to yield high quality logs (eg. sawlogs, veneer logs etc) within acceptable
timeframes. The identification of viable market opportunities for plantation hardwood thinnings will
enhance the profitability for forest growers through the offset of thinning costs. Another benefit to
the forest grower in knowing the best market opportunities for thinnings is that they can then
develop optimal silvicultural regimes to maximise return on investment. Additional benefits accrue
for processors and manufacturers experiencing shortages in traditional resource supply, where
utilisation of the thinnings could provide new opportunities and/or sustainability of their operations.
The social, environmental and economic benefits of hardwood plantations are well documented.
A major impediment to increased investment in hardwood plantations in Queensland and northern
New South Wales is investor uncertainty and lack of knowledge regarding wood quality, product
and market opportunities. The non commercial thinning of plantations represents significant lost
opportunities to value add within the plantation.
1.1
Objectives of the Study
The overall aim of the study was to evaluate the wood quality and properties of thinnings-aged
plantation hardwoods from sub-tropical Australia and assess processing and product options for the
resource. The study can be seperated into two key areas. The first part was the generation of the
fundamental wood qualities and mechanical properties information to build on the data base being
developed to better characterise and understand the changing properties associated with plantation
grown hardwood. The second component was to provide some hardwood plantation thinnings
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material to various industry members to allow the thinnings resource to be trialled in a variety of
processors and product areas.
The target resource for the study was Eucalyptus and Corymbia species that are currently preferred
for hardwood plantation development in the sub-tropics. These include species such as C. citriodora
(spotted gum) and related hybrids, E. pilularis (blackbutt), E. cloeziana (Gympie messmate), E.
dunnii (Dunn’s white gum), E. grandis (rose gum) and E. pellita (red mahogany). Plantation areas
selected for evaluation were sourced from managed plantations less than 10-years-old, representing
anticipated thinnings age and quality. No clear log size or quality criteria was applied, although the
general understanding was that sample logs were to represent what would reasonably be expected as
a non-commercial or low value thinning early in the plantation cycle.
The study was restricted in the volume of material able to be provided to industry participants. This
was mainly attributed to the lack of plantation areas with suitable species and management history
that could be accessed for harvesting. Once suitable and available plantation areas were identified,
the second challenge was being able to select enough volume of logs of a size and quantity that
industry participants were able to process through their existing infrastructure.
An objective of the study was to provide industry with an opportunity to see the thinnings resource
first hand, gain some experience with handling the resource through their existing processes and to
provide information and opinions on how they see the resource potentially fitting into the market
place and what obstacles might need to be overcome. One of the major benefits from this approach
is that product areas that have the greatest potential can be identified and these can be the focus of
future work, whilst those product areas that show little promise at the present time, can become a
lower priority for future research and development.
1.2
Layout of the Report
The report is comprised of several sections. Section 2 includes an overview of the issues faced by
industry utilising hardwood plantation thinnings. Section 3 provides the methodology adopted for
the project including wood properties and mechanical properties testing while Section 4 presents the
results of the testing undertaken. Section 5 includes some concluding comments on the properties
and characteristics. A discussion of some of the broad product groups potentially available to utilise
thinnings from the hardwood plantation resource follows in Section 6 which includes various
industry case studies. Some concluding comments and recommendations for further research
complete the report.
13
2 Issues with Industry Utilisation of Hardwood Plantation
Thinnings
A better understanding of the future thinnings resource is critical to its efficient utilisation and
investment by industry. Availability, stem form, wood properties, logistics, market demand and
price are all influencing factors. Given that the thinnings will be a relatively ‘new’ resource to the
Queensland and northern New South Wales industries, a focus on developing the means of
providing information on these factors to industry is imperative.
The industries that have the potential to utilise the thinnings resource can be broadly broken down
into two categories: a) established industries that may be able to adapt their operations to use the
material to produce either established product types or new product types, and b) new industries that
specialise in the utilisation of a thinnings type resource.
Both categories of industry will need to have knowledge regarding factors such as harvestable
volumes of specific quality log (eg. species, diameter, length, form, wood properties) and cost in
order to decide on the suitability of the resource for specific products and the viability of producing
those products.
There are a number of industries currently operating within Queensland and northern New South
Wales that may be able to ‘gear-up’ to utilise the sub tropical thinnings resource. This approach has
been successfully implemented with processors transitioning to regrowth eucalypts harvested from
native forests in Queensland, New South Wales and Tasmania. Knowledge of the characteristics of
the upcoming resource and the opportunity to trial the material will allow industry to fully capitalise
on the increased availability of this resource through equipment up-grade, product and market
development and long-term business development. Such a scenario could have a number of
potential benefits, such as:
• allowing a gradual resource shift as increasing volumes of thinnings come on-line;
• spreading the risk of losing markets for thinnings across a number of processors;
• developing a competitive marketplace where a number of processors would potentially
utilise the resource increasing the value of the thinnings;
• alleviating the impending resource shortage that a number of current processors are facing,
avoiding plant closure and associated loss of economic and social benefit; and
• attract new investment into the sector.
There are a number of examples of new industries establishing production facilities in regions when
new plantations ‘come on-line’. A proliferation of softwood in Australia in the early 1990’s
provided industry with an incentive to increase the capacity to use mill by-products. A potentially
large supply of such by-products was anticipated and it was around this time that many of the
medium density fibre (MDF) board plants and other wood based panel production facilities were
established (Davidson and Hanna 2004). Advantages of new industries are that they are typically:
• designed specifically for the resource in question;
• set-up close to the resource (eg. efficient); and
• beneficial to regional development including the creation of new employment.
14
3 Wood Material and Methodology
3.1
Resource Selection
Three different plantation resources were chosen for inclusion into the study. Each plantation
consisted of different species, all of which are of importance to future plantation development in
Queensland and/or northern New South Wales. Plantation selection was restricted to those areas
where trees were available for harvest, had at least some history known, and were of a size and
quality deemed to represent young thinnings from the plantation reserves within the Queensland
and northern New South Wales area. The project did highlight the fragmented nature of available
information concerning established hardwood plantations in terms of technical data such as species,
area planted, age, stocking, yield, diameter, tree height and wood quality.
The species included were Gympie messmate, (Eucalyptus cloeziana), blackbutt (E. pilularis) and
red mahogany (E. pellita). The logs sourced from the Gympie messmate and blackbutt plantations
were treated as log batches and predominately allocated to industry participants to process with
minimal assessment. Due to the relative absence of information about red mahogany and the small
population available to the project, a more thorough study with increased data collection was
initiated for this species.
3.1.1 Gympie Messmate (Eucalyptus cloeziana)
Gympie messmate is a large hardwood of scattered occurrence in eastern Queensland from Gympie
in the south to the Atherton district in the north. It is usually found in open-forests or woodlands, on
soils that are generally well drained, acidic and of low fertility, with an annual rainfall of 550 –
2,300 mm (Boland et al 1984). The timber from Gympie messmate has traditionally been used for
heavy engineering construction, railway sleepers, mine timber, posts and poles due to its favourable
natural durability and strength properties (Boland et al 1984; Bootle 2005).
The material for this study was obtained from compartment 208 Yurol State Forest (SF952), located
approximately two kilometres south-east of Pomona (26o23’S, 152o52’E) in south-east Queensland,
Australia. The site was initially planted as a fertiliser trial; however, no fertiliser effect was
registered and the trial was ceased.
The site where the material was harvested from is at an altitude of 105 metres above sea level
(ASL), on variable red earth soils and receives an annual rainfall of 1,470 mm. The site had
previously been planted with rose gum (Eucalyptus grandis) which had been established in 1952
and was clear-felled in 1996. The growth of the rose gum was highly variable across the site which
reflected the high variation in soils and site conditions.
Site preparation consisted of de-stumping using an excavator. The stumps and logging refuse were
windrowed and burnt and the area chopper-rolled to break-up any remaining refuse. The
compartment was cultivated in a single pass using a Stubby TP-3 with an attached set of trailing
discs in January 1997.
The initial stocking of the site was 1,100 stems per hectare. The seedlings for the trial were obtained
from the Beerburrum forestry nursery and had been grown in soil-wall net pots. The site was
planted with Gympie messmate in March 1997 and minor tree refilling was undertaken in mid April
1997 to replace those that hadn’t survived.
15
The site was thinned to 555 stems per hectare in August 1998 and all remaining trees were pruned
to a height of two metres using handsaws. In December 1999, all stems were pruned to a height of
six metres using pole saws. The site was thinned again in March 2005 to approximately 230 stems
per hectare and approximately 25 tonne of the thinnings removed provided the eight year-old
material for the study.
Table 1 summarises the tree measurements taken from a subset of 100 trees selected for harvesting
including diameter at breast height over bark (DBHOB) and estimated usable log length (for the
purposes of the study). Figure 1 provides detail on the allocation of harvested Gympie messmate
logs.
Table 1 Tree measurements of a subset of selected 8-year-old Gympie messmate trees
Average
Standard deviation
Minimum
Maximum
N=100
DBHOB
(mm)
212
32
135
271
Estimated Usable Log
Length (m)
4.8
1.7
2.4
9.6
16
1 Truck Load
(approximately 25 tonne)
0.5 of Shipping Container
to Tasmanian Sawmill
(Forest Enterprises Australia)
Provide industry processing, seasoning
and recovery information targeting light
structural products.
20 Logs for Sawmilling in Brisbane
(Allied Timber Products)
Provide industry processing information
targeting light structural products.
Sawn timber used to gather visual grading
recovery information and mechanical
properties information.
Sawn timber used for secondary
processing information in glue laminated
beams production (Hyne & Son Pty Ltd).
processing information in truss
manufacture (Hurfords Hardwood)
(DPI&F’s Salisbury Research Centre)
processing information in furniture
manufacture (NSW TAFE).
Figure 1 Allocation of Gympie messmate for evaluation.
17
3.1.2 Blackbutt (Eucalyptus pilularis)
Blackbutt is common in coastal New South Wales from south of Bega, near the Victorian border,
northwards into south eastern Queensland as far north as Fraser Island. It is typically found on
slopes of hilly to mountainous country between the sea and the coastal escarpment of the Dividing
Range. Blackbutt mainly occurs on sandy loams or loams, but it is adaptable in relation to soil
requirements and will grow satisfactorily on clays and volcanic soils (Boland et al 1984).
Blackbutt in a plantation environment has good form and growth rate and it is one of the preferred
plantation establishment species in Queensland and north-eastern New South Wales. Traditional
end uses include poles, posts, flooring, panelling, stair furnishings, building framework, and
veneer/plywood (Bootle 2005).
The blackbutt used for the project was sourced from Barcoongere State Forest 826, compartment
7524. This forest is situated about 40 kilometres north of Coffs Harbour (29o56’S, 153o12’E) and
the region’s average annual rainfall is 1,647 mm 1 . The site has a 10 percent slope, a south-east
aspect, and an elevation of approximately 25 to 30 metres ASL on a moderately permeable soil type
Dr1.12 (PPF) 2 .
The site was previously slash pine (Pinus elliottii) plantation planted in 1954, 1955, and 1956 and
this stand was clear felled in 1994-1995. The 1996 blackbutt pre-planting treatment included
tractor clearing, windrow burning, rip-cultivating and mounding, followed by a broadcast aerial
herbicide spray supplemented by a strip spray post planting. The seed was sourced from wild
parent stock within the Barcoongere vicinity and each tree was fertilized with 50g of diammonium
phosphate (DAP). There were no further silvicultural treatments except for a second year targeted
spray with backpacks.
The rows were at four metre spacing and the trees planted at intervals of three metres providing an
eventual survival stocking of approximately 800 stems per hectare (spha). A thinning operation
was conducted in 2005 which removed approximately 360 stems per hectare and provided the nineyear-old material for this project. Table 2 provides a log dimension summary of a random sample of
20 logs removed as part of the thinning operation and provided to the study.
Table 2 Log dimensions of a random sample of 9-year-old blackbutt logs
Average
Standard deviation
Minimum
Maximum
N=20
1
2
Centre Diameter
(mm)
159
8.3
144
171
Log Length
(m)
2.8
0.5
2.4
3.6
Bureau of Meteorology
NSW Department of Land & Water Conservation Soil Profile 28
18
3 Truck Loads
(approximately 75 Tonne)
2 Truck Loads to Hardboard Production
(Australian Hardboards)
Provide industry processing information on
hardboard production.
0.5 of Shipping Container to Tasmanian
Sawmill
(Forest Enterprises Australia)
Provide industry processing, seasoning and
recovery information targeting light structural
products.
0.5 Truck Load to Round Wood Products
(Permalog)
targeting round wood products.
(Allied Timber Products)
targeting light structural products.
Sawn timber used to gather visual grading
recovery information and mechanical
properties information.
Sawn timber used for secondary processing
information in furniture manufacture (NSW
TAFE).
Figure 2 Allocation of blackbutt for evaluation.
19
3.1.3 Red Mahogany (Eucalyptus pellita)
Red mahogany is likely to be the preferred species for hardwood plantations in tropical north-east
Queensland for land degradation control and timber production (Sun et al 1996; Harwood et al
1997; Keenan et al 1997). Red mahogany is a species native to tropical north Queensland, Papua
New Guinea and West Irian (Indonesia), where it is mainly found on moist sites such as gentle
slopes, creek banks and alluvial plains, with an annual rainfall of 900 - 2200 mm (Boland et al
1984; Harwood 1998). Due to its sporadic distribution, red mahogany timber has traditionally only
been available locally in limited quantities. It is used for flooring, cladding, panelling and general
construction (Boland et al 1984; Bootle 2005).
Experiment plot 785 Atherton, located approximately six kilometres north-east of Babinda (17o18'S,
145o58'E) in north-east Queensland, provided the material for the project. The initial purpose of the
experiment was to investigate the growth of red mahogany, Queensland maple (Flindersia
brayleyana), brown salwood (Acacia aulacocarpa) and silver quandong (Elaeocarpus grandis) and
investigate whether mixtures of these species resulted in greater or lesser productivity than
monoculture stands.
The plantation site is at an altitude of 25 metres ASL, on metamorphic red podsolic soil and
receives a average annual rainfall of 4,050 mm. At the time of establishment, site preparation
consisted of broad-acre cultivation with planting lines ploughed at two metre intervals.
Experimental plots consisted of eight rows by 14 trees at two metre spacings to provide a stocking
of approximately 2,500 stems per hectare.
Walkamin nursery provided the seedlings sourced from seed batch 5183, which originated from a
seedling seed orchard comprised of trees of West Irian, Indonesia provenance, located at Kairi,
North Queensland. The experimental plots were established between February and March 1997
with pre- and post-planting weed control conducted using herbicide to ensure the tree rows were
kept weed free until canopy closure was established.
The trees were thinned to approximately 1,600 stems per hectare in 1999 (ie. at age 2-years) and
pruned to three metres. In 2001 (ie. at age 4-years), a further thinning reduced the stocking to 950
stems per hectare and pruning was undertaken to a height of eight metres. Another thinning
operation took place in 2005 to provide a target stocking of 550 stems per hectare. This latest
thinning operation provided the 8.5-year-old material used in this study.
Figure 3 provides detail on the allocation of harvested red mahogany logs, while Table 3 provides a
summary of the number of logs and volume for the different log allocation. Table 4 provides detail
of the individual logs including merchandising and allocation.
Table 3 Number of red mahogany logs and volumes for each log allocation
Log Allocation
Veneer
Sawlogs
Poles
Total
Number of Logs
4
14
9
27
Volume of Logs (m3)
0.296
1.884
0.729
2.909
20
23 Harvested Logs
(sourced from 22 trees)
4 x Veneer Billets
(Big River Timbers)
Provide industry processing and manufacturing
information targeting plywood products.
9 x Round Wood Poles
Providing mechanical properties information
targeting round wood products.
14 x Sawlogs
(Richards Sawmill)
Provide industry processing information and
recovery information
Sawn timber used to gather visual grading recovery
information and mechanical properties
information.
Figure 3 Allocation of red mahogany for evaluation.
21
Table 4 Harvested 8.5-year-old red mahogany logs and origin of test pieces
Tree ID
No.
1
2
3
4
5
6
7
8
10
11
12
13
14
16
17
17a
18
19
20
22
25
26
27
3.2
Harvested
Log Length
(m)
4.9
4.9
4.8
4.9
4.7
4.8
4.8
4.7
3.8
2.8
4.8
4.8
4.8
4.9
4.8
4.9
3.3
4.8
4.8
4.8
4.8
4.8
4.8
Centre
Diameter
(mm)
156
147
210
236
243
185
200
225
199
200
132
202
171
238
252
209
204
218
223
215
157
184
213
Merchandised Log Merchandised Log
1 length (m) and
2 length (m) and
Allocation
Allocation
2.8 –pole
2.8 –pole
4.0 –pole
1.5 –veneer
2.9 –sawlog
1.5 –veneer
2.8 –sawlog
4.0 –pole
4.3 –sawlog
4.6 –sawlog
3.5 -sawlog
2.7 –sawlog
2.8 –pole
4.0 –pole
4.0 –pole
1.5 –veneer
2.9 –sawlog
1.5 –veneer
2.4 –sawlog
4.7 –sawlog
3.1 –sawlog
4.6 –sawlog
4.5 –sawlog
4.7 –sawlog
3.8 –pole
4.0 –pole
3.3 -sawlog
Data Analysis: Box Plot
Most of the quantitative data is presented with box plot charts, which is a convenient way to quickly
compare sets of data visually. A box plot is a chart that indicates the central tendency of the values,
their variability, the symmetry of the distribution, and the presence of outliers (ie. values very
different from the others). Box plots are often used to compare several sets of data.
Order statistics provide a way of estimating proportions of the data that should fall above and below
a given value, called a percentile. The pth percentile is a value, Y(p), such that at most (100p)% of
the measurements are less than this value and at most 100(1- p)% are greater. The 50th percentile is
called the median. Percentiles split a set of ordered data into hundredths, deciles split ordered data
into tenths and quartiles split the ordered data at 25%, 50% and 75%.
There are several ways to display a box plot. This report uses the following format:
•
•
•
•
the lower edge of the box represents the first quartile Q1,
a black horizontal line represents the median Q2 ,
a red horizontal line represents the average,
the upper edge of the box represents the third quartile Q3
22
Two intervals are defined on either side of the first and third quartiles:
IQ1 = [Q1 - 1.5 × (Q3 – Q1) , Q1]
IQ3 = [Q3 , Q3 + 1.5 × (Q3 – Q1)]
•
•
•
•
3.3
The lower part of the box plot reaches from Q1 to the value nearest to the lower bound of
IQ1, while remaining within IQ1,
The upper part of the box plot reaches from Q3 to the value nearest to the upper bound of
IQ3, while remaining within IQ3,
The values underneath the lower part and above the upper part are represented individually
by circles. These circles are filled in when the values are more than 3 times the distance
between the quartiles (Q3 – Q1), and are empty if they are within that interval,
The minimum and maximum values are shown in the box plot.
Small Clear Wood Properties
3.3.1 Basic Density
Basic density is a measurement of the actual wood mass (with all moisture removed) and is
calculated as the oven-dry mass of a timber section divided by its green (saturated) volume. Basic
density reflects the fibre wall thickness and the number of fibres per unit mass and is, therefore, a
useful indicator of the timber’s paper and pulping properties, and influences other wood properties
such as hardness, strength and workability. Basic density, when combined with moisture content
information, can also be used to estimate the weight (and density) of green timber, for example, to
determine freight load weights.
In this research, basic density has been determined by using the test method outlined in Australian
and New Zealand Standard AS/NZS1080:3-2000 Timber – Method of test – Method 3: Density
(Standards Australia 2000). In this method, the green volume of a test piece is determined by water
displacement before being oven-dried to remove all moisture. Basic density is calculated as the ratio
of oven-dry weight (grams) to the weight (grams) of displaced water using the following equation:
Basic Density (kg/m3) = (oven-dry weight/green volume)*1000.
Note that the weight of displaced water in grams is equal to the volume of displaced water in
millilitres.
Disks were taken from the small end and butt end of ten randomly selected logs from both the
Gympie messmate and blackbutt batches; while for the red mahogany, a small end and butt disk
were removed from all 23 sample logs. Two diametric wedges were removed from each disk and
were each further divided into four sections representing inner heartwood, intermediate heartwood,
outer heartwood and sapwood.
3.3.2 Heartwood /Sapwood Proportions
The proportion of heartwood and sapwood has utilisation implications particularly in lyctine
susceptible species or where the timber is to be used in a weather exposed application. A small
sapwood band is generally desirable as it means less timber is wasted if the sapwood is required to
be removed or less chemical preservatives are required if the sapwood is to be treated.
23
Heartwood cannot be successfully impregnated with preservative using current technologies,
therefore, in some circumstances (eg. where the natural durability of the heartwood is low), a wide
sapwood band is beneficial, as this will provide a greater zone of treatment.
Disks were taken from the small end and butt end of ten randomly selected logs from each of the
Gympie messmate and the blackbutt batches; while for the red mahogany, a small end and butt disk
were removed from all 23 sample logs. These disks provided the medium for measuring heartwood
and sapwood proportions. The disks were sprayed with dimethyl yellow to stain and demarcate the
heartwood zone. The sapwood and heartwood widths were measured in a radial direction at four
points across each disk. Sapwood was recorded as a measure of width (in a radial direction) while
heartwood proportion was calculated as a percentage of the disk basal area under bark.
3.3.3 Extractives Content
Wood contains small amounts of extraneous components which do not form part of the cell wall
structure, but are probably present, at least in part, as cell contents. Consequently, they can often be
extracted from the wood by means of a suitable solvent (organic solvents or sometimes water)
without destroying the structure of the wood, and therefore are termed extractives.
Extractives are extremely varied in their chemical nature and embrace many different classes of
organic compounds, including tannins, resins, essential oils, fats, terpenes, flavanoids, quinones,
carbohydrates, glycosides and alkaloids (Farmer 1967). These components are responsible for some
of the characteristic features of individual timbers, such as odour, colour and durability.
Using a test method derived by TAPPI (2001), the extractive contents of the heartwood and
sapwood of each species were measured using both water and dichloromethane as solvents. For
sample preparation, sections of sapwood and heartwood were collected from disk pieces. For each
species, the heartwood sections were combined and ground into a powder-like consistency. From
the powdery mix, two separate test samples were removed with the balance being discarded. The
same process was repeated for the sapwood sections. The test samples represent the average of 10
Gympie messmate and blackbutt trees and 22 red mahogany trees.
3.3.4 Hardness
The hardness of a timber indicates its ability to resist indentation and ease of working with tools and
machinery. Hardness has traditionally been used as a means to compare species for suitability in
applications typically subjected to indentation pressure, such as flooring. Hardness of a species is
closely related to its capacity to resist abrasion (ie. wearing), which is another important property to
consider when selecting species for flooring, bench tops and other specialist components where
sound wearing properties are necessary.
Hardness was measured by the Janka hardness test in accordance with British standard BS373:1957
Methods of testing small clear specimens of timber (British Standards Association 1957), which
requires a steel ball with a diameter of 11.28 mm to be pressed into a test piece until the ball has
penetrated to a depth equal to half its diameter. Two tests were undertaken on the radial and
tangential faces of each test sample. The maximum force necessary to press the ball is measured in
kilonewtons (kN) and is recorded as the hardness of the timber. To allow comparison with
24
published hardness information, the results of testing presents the average of tangential and radial
side grain hardness.
3.3.5 Shrinkage and Unit Shrinkage
Shrinkage will occur in wood after the moisture content falls below a particular level, called the
‘fibre saturation point’. At this point, the wood cell cavities are empty of water, but the cell walls
are still saturated. As moisture is removed from the cell walls, the timber shrinks until it reaches the
local equilibrium moisture content (EMC), where moisture content of the wood stabilises to that of
the surrounding air. A measurement of the shrinkage that will occur in timber as it dries (or seasons)
provides processors with an indication of the dimensions that must be sawn from green timber
(necessary extent of over-cutting) to ensure that seasoned timber will be available in the required
dimensions. Different species have different rates of shrinkage.
Unit shrinkage is another important measure that provides an indication of the dimensional change
that can be expected with seasonal variations, where timber will either increase or decrease in
moisture content as the surrounding EMC fluctuates. Unit shrinkage is expressed as the percentage
of dimensional change per one percent change in moisture content and can be applied between
about 5% and 25% moisture content where the relationship is linear.
The test method adopted was similar to that described by Kingston and Risdon (1961). Test pieces
were cut to the standard size for shrinkage testing (100 mm x 25 mm x 25 mm) and had true radial
and tangential faces with length parallel to the grain (Kelsey and Kingston 1957). After the green
moisture contents of the samples were determined in accordance with Australian and New Zealand
Standard AS/NZS1080.1:1997 Timber –Method of Test –Method 1: Moisture content Standards
Australia 1997), the samples were weighed and had length, width and thickness measurements
made at regular intervals, until approximately 12% moisture content had been reached. Samples
were then reconditioned and redried with measurements taken at about 12% and 5% moisture
content before the samples were oven dried to a constant dry weight. The measured shrinkage of the
test piece from green to air dry is presented as a percentage of the original size of the test piece.
3.3.6 Strength Testing
The Modulus of Elasticity (MOE) is a measure of the ability of timber to resist deflection under
loads, ie. its stiffness. The measurement of stiffness is to enable or determine structure
serviceability. For example, a lintel over a door must be sufficiently stiff to prevent excessive
deflection. If large deflections occurred, the door would jam due to the ‘sag’ in the lintel.
The Modulus of Rupture (MOR), or bending strength, is a measure of the ultimate short-term load
carrying capacity (breaking point). This measure of bending strength indicates the maximum load
that can be applied to a timber section without resulting in ultimate failure (breakage).
The small clear strength testing was conducted in accordance with Mack (1979). Small clear timber
samples with a dimension of 20 mm x 20 mm and 300 mm in length were centre-point loaded. The
magnitude of deflection for given loads was recorded for MOE and the force required to break the
sample recorded for MOR.
Average MOE and MOR values for each batch were compared with the limiting values for standard
seasoned strength group ratings described in Australian and New Zealand standard
25
AS/NZS2878:2000 Timbers - Classification into strength groups (Standards Australia 2000b),
which are reproduced in Table 5.
Table 5 Strength group ratings for seasoned timber (AS/NZS 2878:2000)
Strength
Measure
MOR (MPa)
MOE (GPa)
3.4
SD1
150
21.5
SD2
130
18.5
SD3
110
16.0
Strength group
SD4
SD5
SD6
94
78
65
14.0
12.5
10.5
SD7
55
9.1
SD8
45
7.9
Full Section Characteristics and Properties
Traditionally, small clear strength testing has been used to establish a species strength group and
visual grading used to determine the structural grade of an individual piece of structural timber.
Combined, these two attributes have been used to assign a stress or F grade (see section 3.4.2 for
further explanation). While this has worked effectively for many years, with the changing nature of
the forest resource (eg. from mature native forest to regrowth and young fast grown plantations),
there is a desire to better understand the strength properties of timber sections and to more
accurately define its potential for final products. Strength testing full section pieces (in-grade
testing) aids in this process by determining the Modulus of Elasticity (MOE) and Modulus of
Rupture (MOR) for each individual piece of timber in a form intended for final use and therefore
more accurately characterises the resource.
The timber used to undertake visual grading assessment was used to undertake the full section
strength testing once visual grading was completed. Testing was conducted in accordance with
Australian and New Zealand Standard AS/NZS4063:1992 Timber –Stress-graded –In-grade
strength and stiffness evaluation (Standards Australia 1992).
3.4.2 Visual Grading –Structural
Sawn Gympie messmate and blackbutt timber of a structural dimension (ie. greater than 25mm
thickness) resulting from the sawing trial undertaken at Allied Timber Products (ATP) were
seasoned and machined to either 70 mm x 30 mm or 90 mm x 30 mm. Given the sawing was
conducted through the standard ATP process designed for softwood, the higher shrinkage rate of the
plantation hardwood during seasoning prevented a standard dressed dimension of 35 mm thickness
from being achieved without a high level of ‘hit and miss’. The thickness of 30 mm was chosen to
ensure clean surfaces were available for effective visual grading.
The sawn red mahogany of a structural dimension resulting from the trial undertaken with Richards
Sawmilling at Rappville in northern New South Wales was a nominal 100 mm x 38 mm dimension.
These boards were also seasoned, but not machined prior to grading.
Visual grading was undertaken in accordance with Australian standard AS2082:2000 TimberHardwood-Visually stress-graded for structural purposes (Standards Australia 2000a). This
standard categorises timber pieces of a structural quality into Structural Grades from one to four
26
with Structural Grade 1 having the best structural properties. A minimum length section was
deemed to be 2.4 metres, the standard framing stud length in Queensland.
The species strength group which is derived from small clear strength testing (see section 3.3.6) can
then be used in combination with the structural grade obtained from visual grading to allow a stress
grade (F-grade) to be determined for each section, as illustrated in Table 6. Specific timber stress
grades are used in structural designs and building plans to specify required strengths for
construction.
Table 6 Stress grade (F-grade) determination for seasoned timber (AS2082:2000)
Strength
group
SD1
SD2
SD3
SD4
SD5
SD6
No. 1
structural
F43
F34
F27
F22
F17
F14
Stress grade (F-grade)
No. 2
No. 3
structural
structural
F34
F27
F27
F22
F22
F17
F17
F14
F14
F11
F11
F8
No. 4
structural
F22
F17
F14
F11
F8
F7
3.4.3 Round Wood Strength Testing
Current structural design procedures for round wood products, as outlined in Australian standard
AS1720.1:1997 Timber structures Part 1: Design methods (Standards Australia 1997), rely on
working stress principles and assumed factors for safety, closely coupled with material properties
derived from the strength group/stress grade system used for timber design. For any particular
species, the appropriate stress grade is derived from its unseasoned strength group as reproduced in
table 7.
Table 7 Relationship between strength groups and F-grades for round wood (AS1720.1:1997) and corresponding
classification values (AS/NZS2878:2000)
Strength
group
Stress grade
S1
S2
S3
S4
S5
S6
S7
F34
F27
F22
F17
F14
F11
F8
Modulus of
Elasticity
(MPa)
16,300
14,200
12,400
10,700
9,100
7,900
6,900
Modulus of
Rupture
(MPa)
103
86
73
62
52
43
36
The link between strength groups and stress grades is however based on the assumption that the
round wood products have been cut from mature trees. For poles having a mid-length diameter of
less than 250 mm, allowances are made for immature timber. For Eucalyptus and Corymbia species,
this allowance is only relevant where the pole diameter is less than 125 mm and may be estimated
by multiplying the stress grade by the appropriate factor as outlined in Australian Standard
AS1720.1:1997 Timber structures Part 1: Design methods (Standards Australia 1997).
27
Round wood strength testing was completed for red mahogany poles using a four point test method
in accordance with Australian Standard AS/NZS4063:1992 Timber –Stress-graded –In-grade
strength and stiffness evaluation (Standards Australia 1992).
3.4.4 Plywood Testing
The equipment used in the rotary peeling process used to produce veneers for plywood production,
dictates the minimum diameter of log physically able to be peeled. Traditionally only large diameter
logs of high quality were accepted, however industry in general are adapting to a changing forest
resource to accommodate smaller log diameters and lower grade qualities. This has been achieved
through technology advances such as lathes that utilise power-driven feed rollers allowing spindles
to either be of smaller diameter or totally removed.
The small diameters of the plantation hardwood thinnings used by the study placed great restrictions
on the quantity of material available for plywood testing. The largest four red mahogany logs (small
end diameters ranged between 232 mm and 252 mm) were the only logs suitable. These logs were
provided to Big River Timbers at Grafton, New South Wales where they were rotary peeled on a
1.2 metre lathe with resulting veneers used to produce two 1.2 by 1.2 metre plywood sheets, of 12
mm thickness containing five veneer layers.
Four point bending tests parallel to the face grain were conducted on test pieces (1050 mm x 300
mm) removed from the two plywood sheets in accordance with Australian and New Zealand
Standard AS/NZS2098.9:1995 Methods of test for veneer and plywood Method 9: Procedures for ingrade testing of structural plywood (Standards Australia 1995).
To determine the effectiveness of the B-type glue bonds produced from the melamine ureaformaldehyde adhesive, chisel tests were conducted. The test pieces (150 mm x 65 mm x 12 mm)
were removed from the two plywood sheets and analysed in accordance with Australian and New
Zealand Standard AS/NZS2098.2:1996 Methods of test for veneer and plywood Method 2: Bond
quality of plywood (chisel test) (Standards Australia 1996).
3.4.5 Glued Laminated Beam Testing
Glued laminated beams or ‘glulam’ are manufactured from seasoned sawn timber and are often
finger-jointed to provide the desired length. They are laminated together with a suitable adhesive to
provide the desired beam depth. Glued laminated beams can be manufactured to almost any length,
size and shape, limited only by the manufacturing infrastructure, and transport and handling
capabilities. Through appropriate feedstock selection, the design properties of the beam can be
changed by introducing higher strength laminates to the outer laminates, which are subjected to
higher stresses.
The grade designations for glued laminated beams are based on their Modulus of Elasticity (MOE).
The characteristic strengths, Modulus of Elasticity and Rigidity for various GL-grade classifications
of glued laminated timber are described in Australian Standard AS1720.1:1997 Timber structures
Part 1: Design methods (Standards Australia 19970 and are reproduced in table 8.
28
Table 8 Characteristic strengths, Modulus of Elasticity and Rigidity for horizontally laminated glulam grades
(AS1720.1:1997)
Stress
Characteristic strengths (MPa)
grade Bending Tension Shear Compression
Parallel
in
parallel to
to grain Beam
grain
GL18
GL17
GL13
GL12
GL10
GL8
50
42
33
25
22
19
25
21
16
12
11
10
5.0
3.7
3.7
3.7
3.7
3.7
50
35
33
29
26
24
Short
duration
average
Modulus of
Elasticity
(MPa)
18500
16700
13300
11500
10000
8000
Short
duration
average
Modulus of
Rigidity
(MPa)
1230
1110
900
770
670
530
Approximately 90 ungraded, randomly selected Gympie messmate boards with a dressed dimension
of 70 mm by 30 mm and 2.4 metres in length were provided for glued laminated beam manufacture.
Four 4.8 metre beams were produced with a depth of 215 mm and a width of 65 mm, comprising
eight laminates as well as 30 individual finger-joint samples.
Four point static bending tests were conducted in accordance with Australian and New Zealand
standard AS/NZS4063:1992 Timber –Stress-graded –In-grade strength and stiffness evaluation
(Standards Australia 1992) on four metre sections removed from each of the glue laminated beams.
Two sections from each beam were removed to allow the adhesive quality of the glued joints to be
assessed using a cleavage test in accordance with Australian and New Zealand Standard
AS/NZS1328.1:1998 Glued laminated structural timber Part 1: Performance requirements and
minimum production requirements (Standards Australia 1998). The finger-joint samples were tested
using a four-point bending method in accordance with Australian and New Zealand standard
AS/NZS1491:1996 Finger jointed structural timber (Standards Australia 1996).
29
4 Results and Discussion
4.1
Small Clear Wood Properties
4.1.1 Basic Density
4.1.1.1
Within species variation
The results of basic density testing on Gympie messmate, blackbutt and red mahogany are
presented in Figures 4, 5 and 6. The three species display an important density variation from pith
to bark due to the transition phase from juvenile wood towards mature wood. This variation is
around 200 kg/m3 for the three species studied. This represents about 30% of the average basic
density of the tree which is a very important heterogeneity regarding the potential processing
techniques and products conceivable from these trees. Nevertheless, this value is common for
plantation fast-growing eucalyptus and can be managed. This heterogeneity has to be taken into
account for each potential process/product variation and may necessitate specialist grading or
sorting techniques especially when reconstituted timber is envisaged for structural products.
Gympie messmate
Basic Density (kg/m3)
800
Sapwood
Intermediate
Heartwood
Outer Heartwood
Inner Heartwood
710
672
700
672
625
667
586
600
560
620
606
535
580
480
532
500
478
474
400
425
300
Figure 4 Within tree variation of basic density for Gympie messmate
(N= 20 for each zone, 10 trees)
30
Blackbutt
800
Sapwood
700
Intermediate
Heartwood
Outer Heartwood
Inner Heartwood
663
635
582
600
534
578
500
536
529
487
533
451
419
458
448
400
418
392
364
300
Figure 5 Within tree variation of basic density for blackbutt
Red mahogany
800
700
Sapwood
Outer Heartwood
678
682
Intermediate
Heartwood
Inner Heartwood
653
600
568
564
554
561
564
500
463
423
457
455
450
400
414
357
300
330
Figure 6 Within tree variation of basic density for red mahogany
31
4.1.1.2
Comparison between the species of the study
The average basic density for Gympie messmate, blackbutt and red mahogany are compared in
Figure 7. Gympie messmate displays a significantly higher density and less variability compared to
blackbutt and red mahogany, which could be considered an advantage for Gympie messmate.
700
Blackbutt
Gympie messmate
665
645
Red mahogany
658
642
634
600
589
529
528
500
524
516
474
400
426
Figure 7 Intra and inter species variation of basic density for the three species of the study
(N= 80 each for Gympie messmate and blackbutt, and N=230 for red mahogany)
4.1.1.3
Comparison with other eucalypts
The average basic density value for this 8-year-old Gympie messmate of 634 kg/m3 is low in
comparison to the 810 kg/m3 reported by Bootle (2005) for wood from mature native forest trees. It
does however fit within the expected trend reported by Muneri et al (1998) where it was found that
the basic density of 11, 17 and 46 year-old plantation Gympie messmate was 624 kg/m3, 686 kg/m3
and 769 kg/m3 respectively. Clark and Hicks (1996; and 2003) report an average basic density value
of 644 kg/m3 for 12 year-old and 594 kg/m3 for five-year-old material.
The average basic density of 528 kg/m3 for this 9-year-old blackbutt is higher than the 455 kg/m3
reported by Muneri and Leggate (2000) for 4 year-old plantation blackbutt grown in New South
Wales and close to the 534 kg/m3 reported by Clark and Hicks (1996) for 5-year-old material. It is
lower than the 590 kg/m3 reported by Clark and Hicks (2003) for 12-year-old plantation blackbutt.
A basic density value of 567 kg/m3 was reported for 21-year-old plantation blackbutt (Qld
Government 2005). A value of 710 kg/m3 was given by Bottle (2005) for native forest stands.
Muneri et al (2002) report the average basic density for 8.5-year-old plantation grown red
mahogany of 558 kg/m3, which was higher than the study resource (529 kg/m3). Clark and Hicks
(1996) gave a value of 534 kg/m3 for 5-year-old red mahogany, while Boland et al (1984) quoted
764 kg/m3 for wood from mature native forest red mahogany.
32
The variations observed between the different studies presumably indicate significant genetic and/or
environmental effects upon basic density for the three species of this study. Calculation methods
could also explain some observed variation as the authors do not indicate the method that average
basic density is measured (ie. arithmetic mean or circle shape weighted as was adopted for the
study).
The available published data indicates that further increases in basic density required to reach
mature values is important, and it is reasonable to suggest that this may be reached around the age
of 15-25 years, which is close to the final harvest age for a sawlog management regime.
4.1.2 Heartwood /Sapwood Proportions
The proportion of heartwood and the width of the sapwood band are summarised in Figures 8 and 9.
The average sapwood width of 29 mm found in Gympie messmate samples is higher than the 15
mm, 16 mm and 12mm widths reported by Muneri et al (1998) for 11, 17 and 46-year-old
plantation Gympie messmate. The average heartwood proportion of 50% is lower than the 65%,
69% and 87% for the same material. A sapwood width of 18 mm was reported for sapwood width
for 35-year-old Gympie messmate (Qld Government 2005).
Muneri and Leggate (2000) reported sapwood proportions for four-year-old plantation blackbutt as
65% indicating that the heartwood proportion was 35%. The latter figure is significantly lower than
the 63% found in the blackbutt during this study. A Queensland Government (2005) hardwood
advice website quoted a sapwood width of 22 mm for 21-year-old plantation blackbutt.
A heartwood proportion of 68% reported by Norton and Muneri (2002) for 8.5-year-old plantation
red mahogany is very similar to the 70% found during this study.
Heartwood Proportion (%)
100
Blackbutt
90
Gympie messmate
Red mahogany
90
81
80
71
64
70
63
70
60
50
63
58
50
40
50
44
30
20
10
21
0
Figure 8 Heartwood proportion in the three species assessed
33
Sapwood Width (mm)
Blackbutt
Gympie messmate
40
Red mahogany
37
35
29
30
25
23
20
29
28
17
17
21
15
17
16
10
9
5
5
0
Figure 9 Sapwood thickness in the three species assessed
N= 20 each for Gympie messmate and blackbutt, and N=46 for red mahogany)
The proportion of heartwood and the sapwood width are very much dependant on the log size and
the growth rate. For example, a small diameter suppressed tree will probably have a smaller
sapwood band and higher heartwood proportion than a tree of the same species and age with high
growth rates. The latter tree would be expected to have a wider sapwood band and lower heartwood
proportion.
4.1.3 Extractive Content
The results from the dichloromethane and water extractions for both heartwood and sapwood
samples are presented in tables 9, 10 and 11.
Table 9 Percentage of weight loss after dichloromethane and water extraction for Gympie messmate
Extraction method
Dichloromethane
Water
Dichloromethane & water
% Heartwood
0.46
10.83
11.30
% Sapwood
0.36
3.93
4.29
Table 10 Percentage of weight loss after dichloromethane and water extraction for blackbutt
Extraction method
Dichloromethane
Water
% Heartwood
0.85
8.61
9.46
% Sapwood
1.33
2.96
4.29
Table 11 Percentage of weight loss after dichloromethane and water extraction for red mahogany
Extraction method
Dichloromethane
Water
% Heartwood
0.67
7.32
7.99
% Sapwood
0.54
5.16
5.71
34
It is interesting that the extractive content values obtained from the heartwood of these plantationgrown trees corresponds with the published natural durability classification of the wood from
mature native forests (Bootle 2005). Gympie messmate, which had the highest extract contents is
rated as a more durable wood (class 1 in-ground). Blackbutt and red mahogany are classified as
class 2 in-ground and display similar heartwood extractive contents which are slightly lower than
Gympie messmate. This preliminary observation needs to be further investigated with durability
tests of plantation trees and could assist in this process of accurately defining durability
classifications for plantation timbers.
4.1.4 Hardness
Figure 10 summarises the Janka hardness testing completed for Gympie messmate, blackbutt and
red mahogany.
Average Transverse Janka Hardness
Blackbutt
Gympie messmate
9
Red mahogany
8.39
8.20
8
7.14
7
6.45
6.21
6.87
6
6.20
5.28
5
4.89
4.73
4
3.50
3
2.97
2
Figure 10 Average transverse Janka hardness (kN) in the three species assessed
Muneri and Leggate (2000) reported a Janka hardness value of 4.0 kN for four year-old plantation
blackbutt. It is uncertain which surface or combination of surfaces this value related to, but it is
lower than 4.9 kN measured during this study.
Muneri et al (2002), reported a Janka hardness value of 4.9 kN for 8.5-year-old plantation-grown
red mahogany. This is lower than average side grain hardness value of 6.2 kN obtained from this
study.
Bootle (2005) quoted Janka hardness values of 12 kN, 9.1 kN, and 12 kN for Gympie messmate,
blackbutt and red mahogany respectively for wood from mature native forest.
35
Hardness is closely related to density and these results can be correlated with those obtained for
basic density.
4.1.5 Shrinkage and Unit Shrinkage
The percentages of tangential and radial shrinkage from green to air dry (12% moisture content) for
Gympie messmate and blackbutt are presented in Figure 11.
Percent Shrinkage @ 12% (Air Dry) Moisture Content
8
Radial
Gympie
messmate
Radial
Blackbutt
Tangential
Gympie
messmate
Tangential
Blackbutt
6.78
7
6
5.38
5.42
4.73
5
4.82
4
4.60
3.34
3
2.39
2.65
3.41
2.05
2
2.70
2.33
2.02
1
1.52
1.22
0
Figure 11 Radial and tangential percentage shrinkage shrinkage from green to 12 % moisture content
(N= 10 each for Gympie messmate and blackbutt)
A hardwoods advice website produced by the Queensland Government (1995) quoted shrinkage
values for 35-year-old Gympie messmate to be 5.9% and 4.2% respectively for tangential and radial
orientations (T/R = 1.4), which are higher than the results obtained from this study (4.60%
tangential and 2.02% radial).
Muneri and Leggate (2000) measured average shrinkage values for four-year-old plantation
blackbutt were 6.7% and 2.3% for tangential and radial shrinkage respectively (T/R = 2.9). While
the radial shrinkage value is similar, the tangential value is higher than that measured during this
study.
While shrinkage was not measured for red mahogany as part of the study, Muneri et al (2002)
report tangential and radial shrinkage values of 5.2% and 1.9% respectively (T/R = 2.7) for 8.5year-old red mahogany.
Figure 12 shows the tangential and radial unit shrinkage for Gympie messmate and blackbutt.
36
% Unit Shrinkage
Radial
Blackbutt
Radial
Gympie messmate
Tangential
Blackbutt
Tangential
Gympie messmate
0.45
0.41
0.4
0.35
0.32
0.28
0.3
0.26
0.25
0.26
c
0.22
0.26
0.25
0.18
0.2
0.16
0.20
0.15
0.17
0.17
0.15
0.13
0.1
0.05
0.07
0
Figure 12 Unit percentage shrinkage calculated from 12% to 5 % moisture content
(N= 10 each for Gympie messmate and blackbutt)
A Queensland Government’s (2005) hardwood advice website, which promotes hardwood
plantations, quotes tangential and radial unit shrinkage values of 0.39% and 0.30% for 35-year-old
respectively for plantation-grown Gympie messmate. These values are higher than the unit
shrinkage values of 0.26% tangential and 0.18% radial obtained during this study.
Muneri and Leggate (2000) reported tangential and radial unit shrinkage values for four-year-old
plantation blackbutt as 0.25% and 0.12% respectively, marginally lower than that obtained during
this study.
While unit shrinkage was not measured for red mahogany, Muneri et al (2002) reported tangential
and radial unit shrinkage of 0.28% and 0.17% respectively for 8.5-year-old red mahogany.
The shrinkage values observed for the trees of this study are significantly lower than the values
observed for mature native forest trees in the literature (Table 12). The T/R ratio is higher in the
trees studied (Figure 13) than in figures quoted for wood from mature native forest trees (Table 12).
High T/R ratios are generally unfavourable because shrinkage induces higher transverse
deformation. Where this is a problem, changes in processing and drying strategies may need to be
adopted and/or products may need to incorporate design principles that allow for high unit
shrinkage.
37
Ratio shrinkages T/R
5
Gympie
messmate
Blackbutt
4.38
4.5
4
3.41
3.5
3
2.36
2.5
2.18
2.34
2
2.07
1.5
1
1.29
1.21
0.5
0
Figure 13 Total percent shrinkage from green to 12 % moisture content
(N= 10 for Gympie messmate and blackbutt)
Table 12 Shrinkage properties for mature wood of native forest species (extracted from Kynaston et al 1994).
Species
Shrinkage
(green to 12% mc)
Unit shrinkage
T/R ratio
T
R
T
R
Gympie messmate
6.2
3.4
0.37
0.21
1.8
Blackbutt
7.3
4.3
0.37
0.26
1.7
Red mahogany
6.3
3.9
0.34
0.27
1.6
Figures 14 and 15 provide a summary of the Modulus of Elasticity (MOE) and Modulus of Rupture
(MOR) results from the small clear bending tests carried out for Gympie messmate, blackbutt and
red mahogany.
38
MOE (GPa)
18
Blackbutt
16
15.3
Gympie messmate
Red mahogany
16.1
13.9
14
12.7
11.8
12
10.4
11.8
11.7
10
9.7
8.9
8
8.2
6
6.8
4
Figure 14 Small clear wood bending MOE in GPa
MOR (MPa)
160
Blackbutt
Gympie messmate
Red mahogany
142
140
126
121
120
106
99
100
104
90
88
80
70
60
40
94
92
49
Figure 15 Small clear wood bending MOR in MPa
39
In accordance with Australian and New Zealand Standard AS/NZS2878:2000 Timber –
Classification into strength groups (Standards Australia 2000), the Gympie messmate test
population satisfied the requirements of SD6 for MOE and SD4 for MOR. Applying the procedure
of Table 2.3 of AS/NZS2878:2000, an overall strength group of SD5 is achieved. The blackbutt test
population satisfies the requirements of SD7 for MOE and SD5 for MOR, for an overall strength
group of SD6. The red mahogany test population satisfied the requirements of SD4 for both MOE
and MOR for an overall rating of SD4.
Muneri and Leggate (2000) had reported MOE and MOR values of 9.1 GPa and 79.8 MPa for fouryear-old plantation blackbutt, but these lower values makes minimal difference when converting to
a seasoned strength group.
Muneri et al (2002) quoted MOE and MOR values of 13.0 GPa and 105.6 MPa for 8.5-year-old red
mahogany, and although the MOR value reflected a SD4 result as with the study samples, the MOE
value reflected a lower seasoned strength group of SD5.
Table 13 gives MOE and MOR properties for mature native forest Gympie messmate, blackbutt and
red mahogany. Comparing these values with those in this study (Figures 13 and 14), confirmed that
the trees from young plantations have lower mechanical properties. This result could be expected
because of the lower density values of the latter resource (Section 4.1.1). Although the mechanical
property test results showed lower values than timber from native forest stands, they are higher than
the mechanical properties achieved by common softwood plantation species grown in the same
area.
Table 13 Seasoned MOE and MOR properties for native stand species (extracted from Bootle 2005).
4.2
Species
MOE (GPa)
MOR (MPa)
Gympie messmate
17
139
Blackbutt
19
144
Red mahogany
18
140
Full Section Characteristics and Properties
4.2.1 Sawn Strength
Summaries of Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) results from the full
section strength testing carried out on the sawn Gympie messmate, blackbutt and red mahogany are
presented in Figures 16 and 17. Information for each species is presented in Tables 14, 15 and 16.
40
MOE (GPa)
20
Blackbutt
Gympie messmate
18.2
18.1
Red mahogany
18.5
18
16
14
13.0
12
12.9
11.6
11.1
11.2
10
10.9
8
6
6.9
6.7
4
4.6
Figure 16 Full section wood bending MOE in GPa
(N= 102 for Gympie messmate, N=66 for blackbutt, and N=54 for red mahogany)
Full Section MOR (MPa)
Blackbutt
Gympie messmate
Red mahogany
140
126
120
111
108
100
80
72
61
70
60
57
56
56
40
37
20
23
17
0
Figure 17 Full section wood bending MOR in MPa
(N= 102 for Gympie messmate, N=66 for blackbutt, and N=54 for red mahogany)
41
The mechanical properties obtained on full size sections display similar MOE values to the small
clear testing but the occurrence of the defects (due mainly to the knotty central core) reduced the
MOR significantly. The full section MOR values are approximately 40% lower than the MOR
observed on small clear testing, and the variation is greater. These results highlight the need to
effectively grade the timber to ensure that the desired strength properties are suitable for product
needs.
Table 14 Full section strength test summary for Gympie messmate
Average
Standard deviation
Minimum
Maximum
Ek (MPa)
Rknorm
Modulus of Elasticity
(GPa)
11.6
2.6
6.7
18.1
11460.0
-
Modulus of Rupture
(MPa)
61.0
23.9
23.1
126.0
27.3
Ek = characteristic value of the Modulus of Elasticity
Rknorm = normalised characteristic strength
Table 15 Full section strength test summary for blackbutt
Average
Standard deviation
Minimum
Maximum
Ek (MPa)
Rknorm
(GPa)
12.9
2.6
6.9
18.2
12664.0
-
Modulus of Rupture
(MPa)
70.3
15.5
37.2
107.8
48.3
Table 16 Full section strength test summary for red mahogany
Average
Standard deviation
Minimum
Maximum
Ek (MPa)
Rknorm
(GPa)
11.1
3.1
4.1
18.5
11230.0
-
Modulus of Rupture
(MPa)
56.9
20.1
17.0
111.4
26.6
While full section strength testing would normally characterise a population or batch of timber’s
strength properties, Figures 18, 19 and 20 have been produced to provide an indication of true
strength properties in terms of F-grades at an individual piece level. Compared with the grade
recovery figures produced for the same samples when visually graded (see Figures 21, 26 and 31 in
section 4.2.2), the recovery is much higher overall as well as higher F grades being achieved.
It is important to note that structural hardwood is normally visually graded (Section 4.2.2) with the
lowest grade normally being F14. Lower F grades have traditionally been reserved for softwood
42
products with the low end grades (ie. F4 and F5) channelled into utility product (eg. noggings etc).
The test data highlight the potential problems with using a visual grading process designed for a
mature native forest resource and the potential undervaluing that this process could have with
plantation grown timbers.
F-grades
30%
25%
25%
22%
% of Boards
20%
18%
16%
15%
13%
10%
5%
5%
3%
0%
0%
F34
F27
0%
0%
F22
F17
F14
F11
F8
F7
F5
F4
Figure 18 Gympie messmate full section F-grade distribution (extrapolated from full section strength testing)
F-grades
30%
27%
25%
23%
21%
% of Boards
20%
15%
15%
10%
8%
5%
5%
2%
0%
0%
0%
F5
F4
0%
F34
F27
F22
F17
F14
F11
F8
F7
Figure 19 Blackbutt full section F-grade distribution (extrapolated from full section strength testing)
43
F- grade
45%
41%
40%
35%
% of Boards
30%
25%
20%
20%
15%
13%
10%
6%
5%
7%
6%
4%
2%
2%
0%
0%
F34
F27
F22
F17
F14
F11
F8
F7
F5
F4
Figure 20 Red mahogany full section F-grade distribution (extrapolated from full section strength testing)
4.2.2 Visual Grading - Structural
4.2.2.1
Gympie messmate
The results of the visual grading of sawn boards of a structural dimension to Australian Standard
AS2082:2000 Timber-Hardwood-Visually graded for structural purposes (Standards Australia
2000) are presented in Figure 21. The primary reasons (excluding distortion and end splits) for
boards failing to meet the allowances set within AS2082:2000 for each structural grade are
presented in Figures 22, 23, 24 and 25.
F-grades
70%
65%
60%
% of Boards
50%
40%
30%
20%
20%
9%
10%
0%
0%
0%
1%
F34
F27
F22
F17
4%
0%
0%
0%
F7
F5
F4
0%
F14
F11
F8
Reject
Figure 21 Grade recovery of Gympie messmate boards in accordance with AS2082:2000
44
1%
1%
3%
4%
48%
43%
Heart/Pith
Heart Shake >check
Individual Knot
Knot cluster
Wane
Gum, resin latex Pockets
Figure 22 Primary reasons for Structural Grade 2 (F14) Gympie messmate boards failing to meet a higher grade.
3%
3%
19%
Individual Knot
Knot cluster
Want
Overgrowth of injury
75%
45
10%
20%
Heart Shake >check
Individual Knot
Knot cluster
70%
3%
1%
1%
3%
Heart/Pith
Heart Shake >check
14%
1%
Individual Knot
Knot cluster
21%
22%
Want
Wane
Borer Holes
Primary rot
34%
Figure 25 Primary reasons for reject Gympie messmate boards failing to meet a higher grade.
Distortion and end-splits were also recorded for each board. Table 17 presents the number of boards
for each grade that although meeting the grading standard for reasons such as natural imperfections,
would be excluded due to distortion and/or end-splits being in excess of the limitations set within
AS2082:2000.
46
Table 17 Number of Gympie messmate boards excluded due to distortion and end-splits
Structural Grade
Bow
Spring
Twist
1
2
3
4
Reject
4.2.2.2
1
1
22
End-splits
Proportion of total
boards (%)
0.3
0.3
14.3
27
Blackbutt
The results of the visual grading of sawn boards of a structural dimension to Australian Standard
2000) are presented in Figure 26. The primary reasons (excluding distortion and end splits) for
boards failing to meet the allowances set within AS2082:2000 for each structural grade are
presented in Figures 27, 28, 29 and 30.
F-grade
60%
51%
50%
% of Boards
40%
30%
22%
20%
15%
9%
10%
3%
0%
0%
0%
0%
F34
F27
F22
F17
0%
0%
F5
F4
0%
F14
F11
F8
F7
Reject
Figure 26 Grade recovery of blackbutt boards in accordance with AS2082:2000
47
13%
Individual Knot
Knot cluster
Tight Gum veins
20%
67%
Figure 27 Primary reasons for Structural Grade 2 (F11) blackbutt boards failing to meet a higher grade.
20%
40%
Individual Knot
Knot cluster
40%
48
Knot cluster
100%
Heart/Pith
8%
3%
Fracture
13%
Heart Shake >check
3%
Individual Knot
5%
5%
Knot cluster
5%
Want
3%
13%
Wane
Termite Galleries
Gum, resin latex Pockets
18%
24%
Primary rot
Figure 30 Primary reasons for reject blackbutt boards failing to meet a higher grade.
Distortion and end-splits were also recorded for each board. Table 18 gives the number of boards
for each grade that although meeting the standard for reasons such as natural imperfections, would
be excluded due to distortion and/or end-splits being in excess of the limitations set within
AS2082:2000.
49
Table 18 Number of blackbutt boards excluded due to distortion and end-splits
Structural grade
Bow
1
2
3
4
Reject
4.2.2.3
Spring Twist
End-splits
Proportion of total
boards (%)
1
1
1
1
4
9
Red mahogany
The results of the visual grading of sawn boards of a structural dimension to Australian standard
2000) are presented in Figure 31. The primary reasons (excluding distortion and end splits) for sawn
red mahogany structural boards failing to meet the allowances set within AS2082:2000 for each
structural grade are presented in figures 32, 33, 34 and 35.
F-grade
60%
49%
50%
% of Boards
40%
30%
26%
20%
17%
10%
6%
0%
0%
F34
F27
2%
0%
0%
0%
0%
F8
F7
F5
F4
0%
F22
F17
F14
F11
Reject
Figure 31 Grade recovery of red mahogany boards in accordance with AS2082:2000
50
29%
42%
Loose knot/knot hole
Tight Knots
Knot cluster
29%
Figure 32 Primary reasons for Structural Grade 2 (F17) red mahogany boards failing to meet a higher grade quality.
33%
Tight Knots
Knot cluster
67%
51
33%
Knot cluster
Want
67%
7%
7%
10%
Heart/Pith
Heart Shake >check
Loose knot/knot hole
Tight Knots
Knot cluster
Want
3%
3%
14%
49%
Wane
Primary rot
7%
Figure 35 Primary reasons for reject red mahogany boards failing to meet a higher grade quality.
Distortion and end-splits were also recorded for each board. Table 19 presents the number of boards
for each grade that although make meeting the standard for reasons such as natural imperfections,
would be excluded due to distortion and/or end-splits being in excess of the limitations set within
AS2082:2000.
52
Table 19 Number of red mahogany boards excluded due to distortion and end-splits
Structural grade
1
2
3
4
Reject
4.2.2.4
Bow
Spring
Twist
End-splits
2
2
4
1
Proportion of total
boards (%)
14
4
2
10
32
5
1
Visual grading discussion
Heart and heart associated defects (eg. heart shakes) and knots (eg. solitary, clusters, holes) were
the main cause of board downgrade in all three species included in the study. Given the relatively
small diameter of the logs had resulted in many of the boards being removed from within the
‘knotty core’ of the log and close to the log centre (or heart), the presence of these defects is not
surprising.
While the visual grading results reflect a high rate of reject boards, the full section strength testing
that was undertaken on the same boards suggests that suitable strength properties do exist in a
higher proportion of boards than reflected by the visual grading results (Section 4.2.1). The reason
for the different result between the visual grading and the full section strength testing is probably
that the visual grading standard was prepared for a native forest hardwood resource in mind and
implies that this standard is not appropriate for the grading of plantation-grown sawn structural
material.
4.2.3 Round Wood Strength Testing (Red Mahogany)
Nine red mahogany poles were in-grade tested for Modulus of Elasticity (MOE) and Modulus of
Rupture (MOR). A summary of the test results are presented in table 20.
Table 20 Strength test results for red mahogany poles
Attribute
Number
Average
c. v. (%)
Minimum
Maximum
(GPa)
9
15.4
24
11.5
23.6
Modulus of Rupture
(MPa)
9
76.9
8.7
65.4
90.2
While the number of poles tested was too small for accurate application of a stress grade to this
material, comparison with Table 2.4, Australian standard AS1720.1:1997 Timber structures Part 1:
Design methods (Standards Australia 1997) suggests a grade of F14 to F17 may be applicable. This
grade would be compatible with the design grade for an S4 species under AS1720.1:1997 (Table
6.1). However, this observation could not be confirmed in this trial because the green strength group
was not evaluated.
The round wood MOE is significantly higher than full section sawn timber MOE and even clear
wood MOE. In comparison, the MOR for round wood is closer to that for the clear wood than the
full section sawn MOR. Moreover, the variability of these mechanical properties in round wood is
53
lower than that of small clear wood or full section sawn timber. These results confirm the
mechanical performance of natural round wood, in which the strength properties aren’t reduced by
interrupting the continuity of the fibred, as occurs in turned or sawn structural material. This gives a
strong argument for the utilisation of thinnings as round wood products.
Table 21 compares the results from this trial with a selection of those for similar sized material from
a previous study (McCarthy et al 2005). The results of this study are comparable to those of
previous studies.
Table 21 Plantation round wood strength data
Species
Corymbia maculata, ACQ & PEC treated
Eucalyptus cladocalyx, ACQ & PEC treated
E. pellita, untreated (this study)
E. pilularis, ACQ & PEC treated
E. grandis, ACQ & PEC treated
Pinus radiata, CCA treated
Strength Group
(AS/NZS2878:2000)
S2
S3
(S2)
S2
S3
S6
Mean MOR
(MPa)
103
96
77
67
46
39
4.2.4 Plywood Testing
A summary of the parallel to face grain bending tests conducted on the 12 mm red mahogany
plywood samples are presented in table 22, while the glue bond quality of each test sample glue line
and overall bond quality are summarised in table 23.
Table 22 Modulus of Elasticity and Rupture (parallel to the grain) in red mahogany plywood samples
Average
Standard deviation
c.v. (%)
Minimum
Maximum
(GPa)
15.7
2.3
14.6
13.5
18.9
Modulus of Rupture
(MPa)
127.0
14.3
11.3
109.2
141.6
Table 23 ‘B’ type glue bond test results (melamine-urea-formaldehyde) for red mahogany plywood
Sample No.
1a
2a
Av 1a & 2a
Note:
Test
6 hour boil
6 hour boil
Score for each glue line
1
2
3
4
7
8
8
5
6
6
8
7
6.5
7
8
6
Average Result
7
6.7
6.8
Pass
1. Scale: 0 = 0% wood failure, 10 = 100% wood failure.
2. Pass criterion: no average glueline less than 2, average all gluelines to exceed 4.
The number of sheets available for testing precludes allocation of stress grades under Australian and
New Zealand standard AS/NZS4063:1992 Timber –Stress-graded –In-grade strength and stiffness
evaluation (Standards Australia 1992). However, given the low coefficient of variation of the
strength and stiffness data (characteristic of plywood), it would be reasonable to expect a stress
54
grade of F17 to F22 from this material, when the data are compared with Table 5.1 within
Australian standard AS1720.1:1997 Timber structures Part 1: Design methods (Standards Australia
1997).
The plywood was bonded with a melamine-urea-formaldehyde adhesive (MUF), classified as a
Type B Bond in Australian standard AS2754:1985. The bond test for this bond type requires water
soaking at 100oC for six hours, followed by a chisel test and wood failure assessment of the
fractured glue-lines in accordance with criteria outlined within Australian and New Zealand
standard AS/NZS2098.2:1996 Methods of test veneer and plywood method 2: Bond quality of
plywood (chisel test) (Standards Australia 1996).
The results summarised in Table 22 confirm compliance of the bonding with the criteria for B
Bonds of AS/NZS2098.2:1996. If exterior applications are envisaged, further testing of suitably
bonded ply to the A Bond specification (72 hour boil) would be required.
4.2.5 Laminated Products
4.2.5.1
Finger-jointed scantlings
A sample of 30 finger jointed test pieces was produced from ungraded Gympie messmate timber at
the same time the glued laminated beams were manufactured. Major defects were removed from
the sections prior to jointing. The samples complied with the specification for finger joint test pieces
specified within Australian and New Zealand standard AS/NZS1491:1996 Finger jointed structural
timber (Standards Australia 1996). When the samples were tested in four-point bending, the results
shown in Table 24 were obtained.
Table 24 Finger-joint bending results for Gympie messmate samples
Attribute
Number
Average
c. v. (%)
5th Percentile
Ek 3
Rk, norm 1
(GPa)
30
13.7
13.9
11.0
13.4
Modulus of Rupture
(MPa)
30
42.4
24.3
28.4
28.7
This material complies with a stress grade of F8, according to Table 2.4, Australian Standard
AS1720.1:1997 Timber structures Part 1: Design methods (Standards Australia 1997) and the
criteria of Clause 10 within Australian and New Zealand standard AS/NZS4063:1992 Timber –
Stress-graded –in-grade strength and stiffness evaluation (Standards Australia 1992). It was
indicated in Section 4.1.6 that the Gympie messmate material had a strength group of SD5; so
referring to Table 6, this grade would be yielded from Structural Grade No. 4 timber of this strength
group. This demonstrates that the finger joints have retained equivalent strength class to a typical
structural grade of plantation hardwood.
3
Ek and Rk,norm are characteristic values for stiffness and strength respectively calculated as in Australian and New
Zealand Standard AS/NZS4063:1992 Timber -Stress-graded -In-grade strength and stiffness evaluation.
55
4.2.5.2
Glued laminated beam testing
The four point static bending test results for the glue laminated beams are presented in Table 25 and
summarised in Table 26. The results of the glue joint cleavage tests in Table 27 indicate that a
successful glue bond was achieved. The summarised results of the finger-joint bending tests are
presented in Table 28.
Table 25 MOE and MOR results for the Gympie messmate glued laminated beams
Sample No.
M.C.
(%)
12
12
12
12
Beam 1
Beam 2
Beam 3
Beam 4
Breadth
(mm)
64.5
64.7
64.6
64.5
Depth
(mm)
216.0
215.5
215.0
216.5
MOE
(GPa)
24.41
23.49
22.38
21.91
MOR
(MPa)
48.87
38.65
40.72
52.47
Table 26 Summary of MOE and MOR results for the Gympie messmate glued laminated beams
Attribute
(GPa)
23.0
4.8
1.1
Average
c.v. (%)
Standard deviation
N=4
Modulus of Rupture
(MPa)
45.2
14.6
6.6
Table 27 Glue joint cleavage test results
Average
Standard deviation
Minimum
Maximum
Wood fibre failure
(%)
83.7
24.3
0
100
Table 28 Finger-joint bending test results
Average
Standard deviation
Minimum
Maximum
(GPa)
13.7
1.9
10.6
19.1
Modulus of Rupture
(MPa)
42.4
10.3
23.3
66.4
The sample size was too small to allow the calculation of characteristic values, hence definitive
allocation to laminated beam (GL) grades is not possible. However, given the low CVs obtained
(ie. characteristic of glulam), it would be reasonable to expect this material would comply with GL
10 or 12.
Cleavage tests, performed to Australian and New Zealand Standard AS/NZS1328.1:1998 Glued
laminated structural timber Part 1: Performance requirements and minimum production
requirements (Standards Australia 1998) were conducted on two samples from each of the four
Gympie messmate beams. The results were averaged, and the data are summarised in Table 29.
56
Table 29 Cleavage test results from Gympie messmate glued laminated beams
Attribute
No. beams tested
Average % wood failure
Average min. glueline %
No passed
Result
4
83.7
57
4
All beams passed the wood failure criteria of AS/NZS1328.1:1998, indicating successful glue
bonding.
Compared to sawn clear wood or full section MOR values, the results obtained on laminated
products are lower due to finger joint weakness. It would be expected that improvements to gluing
procedures and glue system would achieve higher strength properties and consequently a higher
strength class could be gained. This may be possible if further investigations are conducted.
57
5 Conclusions on the Properties and Characteristics
5.1
Clear Wood Properties
Intrinsic average wood properties from the three species sampled included significant lower
physical and mechanical properties (density, stiffness, hardness and strength) when compared to the
same species from native forests. For basic density, it is a decrease of 20% and around 40 % for the
other mechanical properties. Nevertheless, these properties remain better than the common
softwood plantation species grown in the same area.
Interesting results were found for shrinkage, which were predominantly lower than the values
quoted in the literature for wood from mature native forest trees. Lower shrinkage benefits sawn
recoveries because less oversized sawing is required, and the timber has greater stability in service.
Conversely, the higher T/R ratio could have a negative impact, and changes in processing, drying
strategies and product design may need to be adopted.
Heartwood proportions in these plantation-grown species varied between 50% and 70%, which is
relatively low compared to the natural resource but probably high compared to other hardwood or
softwood plantation resources. It is important to note that this characteristic depends strongly upon
growth patterns and management systems.
There is a strong need to accurately classify natural durability as this could be a favourable wood
characteristic when compared to the ratings from other plantation timbers grown in Australia or
elsewhere. This would need the development of fast assessment techniques (such as near infrared
spectroscopy or extractive content measurement) since the variability could be high and this
characteristic should be included in genetic and tree breeding programs.
The study has identified the large variation in wood properties that exists between and within the
three plantation resources sampled. The main variations occur between the juvenile and mature
phases which is common for fast growing plantation eucalyptus and can be managed (eg. Lyptus
products from the Brazilian company Aracruz www.lyptus.com.br). This transitional phase spreads
throughout the entire section of the sample logs and is expected to last through until final harvest.
The main adverse effect of the juvenile to mature wood transition is the gradient of wood properties
along the radius which influence processing (especially seasoning) and product quality (eg. density
variation). To overcome these problems, grading and sorting will be important to firstly segregate
based on known properties (eg. low density and high density) and optimise the use of the
heterogeneity in the wood properties.
5.2
Full Section Properties
The full section properties were mainly influenced by the knotty core characteristics. It was
considered that use as round wood (natural size) is the best structural use of the thinnings resource.
The sawn full section MOR values are approximately 40% lower than those observed for small
clear testing and the variation is also much wider. These results highlight the need to effectively
grade to ensure the desired strength properties specific to product needs are capitalised upon. For
Gympie messmate, only 21% of boards visually graded achieved a grade of F14 or better, however,
measured strength properties reflected 43% of the material achieved F14 or better. Blackbutt
58
produced the most noticeable difference with only 3% of boards visually grading at F14 or better
compared to 76% using measured strength properties. Red mahogany also showed similar results
with 49% being recovered at F14 or better compared to 55% when tested.
The laminated products displayed an equivalent strength class to a typical structural grade of
plantation hardwood. Nevertheless when compared to sawn clear wood or full section MOR, the
values obtained on laminated products are lower due to finger joint weakness. It would be expected
that improvements to gluing procedures and glue system would achieve higher strength properties
and as a consequence, a higher strength class could be gained. This may be possible if further
investigations are conducted.
The results from these trials indicated the need for specific grading standards, techniques or rules
for plantation hardwoods.
59
6 Product Opportunities
6.1
Sawn Timber
The production of sawn timber from hardwood plantations is one of the range of products that are
most often considered when evaluating options to gain higher value from the plantation resource.
While logs resulting from plantation final harvests are expected to more easily produce quality sawn
timber, given their expected larger diameter, longer log length and superior quality (especially in
terms of clear wood volume), producing quality sawn timber from the plantation thinnings may be
more difficult.
A wide range of sawn timber product groups exist and each of the groups have specific demands for
quality, dimension and quantity. These product groups can be broadly outlined as follows:
1. utility products eg. pallet and packing case material.
2. heavy structural eg. bridge timbers, large section bearers and joists.
3. light structural eg. house framing, smaller dimension bearers and joists, truss and glued
laminated beam feedstock.
4. high volume appearance products eg. strip flooring, decking and panelling.
5. specialty appearance products eg. furniture components and joinery.
Utility products often require minimal value adding as they are often used unseasoned, with no
profiling or machining and minimal grading. While the product often attracts a lower price in
comparison to other sawn timber product groups, one of the benefits is that lower grade quality
boards can be used, therefore, the opportunity exists to recover substantially more sawn volume
such as that recovered from the central knotty core of the log.
Sawn hardwood timber from native forests has dominated the domestic market for heavy structural
sawn products, where requirements have included characteristics such as large dimensions and high
structural properties. In particular, the smaller dimension of sawn timber expected to be recovered
from plantation thinnings isn’t expected to be sufficient to service the requirements for these
traditional products. An opportunity does exist to substitute engineered products such as glued
laminated beams manufactured using light structural sawn wood as an alternative to traditional
heavy structural products.
The use of hardwood in light structural applications such as wall framing and roof trusses has
rapidly declined over recent decades with the dominance of the softwood industry. However, there
are signs of demand emerging for sawn, seasoned and profiled product with structural properties
equivalent to or higher than the upper end of readily available structural softwood (ie. MGP 12 and
15). Potential end uses for this product group include smaller dimension bearers and joists, rafters
and truss feedstock, top and bottom plates for I-beam manufacture. It was interesting that this
product area attracted the most enthusiasm from industry participants in these trials. Forest
Enterprises Australia is a prime example of an organisation which has recognised this emerging
demand and have developed using plantation-grown shinning gum (Eucalyptus nitens) marketed as
EcoAshTM, to enter this product group with reported success (see Case Study 1 for additional
information).
Appearance products such as flooring, decking and panelling are targeted by many existing
hardwood sawmills as an effective method to value add their products. The challenge exists to
recover sufficient volume of suitable grade material from plantation thinnings. Recent plantation
60
hardwood recovery studies targeting milled products such as flooring have highlighted the negative
impacts that imperfections characteristic of being sawn timber from plantation logs have on grade
recovery. For example, Leggate (1998) reported a recovery of 23% of the green-off-saw volume for
33 year old western white gum (Eucalyptus argophloia), which mad an appearance grade in
accordance with Australian standard DR97207 -Revision of AS2796 –Appearance grading standard
for hardwood sawn and milled products (Standards Australia 1998). In contrast, hardwood sawmills
in Queensland would usually expect to recover around 90% of the green off saw volume using
native forest logs (Leggate 1998). With current grading standards and market demand for this
product group, the log quality required to achieve economical high grade recoveries is more
achievable from final harvest logs than from logs from young thinnings.
Specialty appearance products include items such as furniture components, joinery and moulding,
and generally require high quality sawn timber (ie. minimal or no imperfections). Despite the
expectation that the small size of plantation thinning logs will result in problems in producing
volumes of sawn timber with minimal or no defects, opportunities may still exist to supply within
this product category due to shorter length requirements than products such as decking and flooring.
Often the required lengths are shorter than those required for products such as decking. The
requirement for shorter lengths means that imperfections can be docked, improving the grade
quality. Opportunities also exist to use alternative technologies such as finger jointing or laminating
to allow docked timber to be reconstructed to produce more desirable dimensions and straight stable
products.
Whilst five broad sawn timber product groups have been described, it would be reasonable to
assume that most if not all producers of sawn timber will process products from within two or more
of the groups outlined above. For example, the sawn timber from the outer heartwood that is higher
in density, contains superior strength properties and contains less imperfections may be separated
out for use as a light structural product. The sawn timber produced from the middle or centre of the
log that containing many imperfections, is lower in density and has lower strength properties may
be diverted to utility products. This provides an example where a high recovery of usable product is
achieved while ensuring the most value can be gained from production.
6.2
Round Wood
Round wood products are potentially ideal to utilise hardwood plantation material, especially from
early rotation thinning operations. Round wood products such as construction poles, vineyard posts,
landscaping products and fence posts are examples. Higher value round wood products, such as
electricity transmission poles would not be expected to be yielded from early rotation plantations,
but they would be a consideration at time of final harvest.
There are two major benefits of round wood products. The first major benefit is the high recovery of
product from raw material because the loss of substantial volume in other product conversion
practices such as sawn timber is not an issue. Round wood products can either be used in the natural
form or ‘shaved’ which is usually undertaken to make a parallel product with a smooth finish. The
second major benefit is that the characteristic design properties in round wood products are superior
to those equivalent sawn sections from the same log.
Use of round wood products in construction has been limited in Australia. Yeates (1999) reported
that perhaps the most challenging aspect of utilising thinning material as round wood in
61
construction lies with the absence of a viable connecting method. A lack of published data on the
characteristic properties, grading standards and appropriate designs are also noted as impediments.
Many of the final applications for round wood products will be in weather exposed applications
resulting in the need for preservative treatment. Recent treatment trials on possible use of small
diameter plantation-grown eucalypt posts in vineyards have shown that the sapwood can be
completely penetrated by standard vacuum pressure techniques (McCarthy et al 2005). Timber
treatment trials on shaved small diameter eucalypts showed that the wood to be treated must be
preconditioned to the appropriate moisture content to achieve the required depth of preservative
penetration (Norton 2006). While the treatment process can successfully boost the durability of the
sapwood region, the heartwood zone is left untreated and therefore natural durability properties are
required. While many of the species being targeted for plantation development in Queensland and
northern New South Wales have historically been regarded as durable, the durability of the
heartwood of young (ie. less than 15-years-old) plantation hardwoods is largely unknown and
predicted to be less than that of the mature native forest resource.
The main species that dominate the local round wood market is the Pinus spp. This resource is often
‘shaved’ or peeled to present a uniform and more aesthetically appealing product to the consumer.
The uneven nature of debarked eucalypt round wood poles (ie. not shaved) would be expected to
make the product only suitable for agricultural markets. While the plantation hardwood resource
can be effectively shaved, the logs appear to undergo extensive splitting and checking and
consequently are undesirable for sale. This problem is suggested to be the major limiting factor in
utilising plantation hardwood in the round wood market.
6.3
Engineered Wood Products
Engineered wood products (EWPs) are manufactured by the adhesion and/or compression of wood
fibres, flakes, laminates or veneer material to a requisite standard and dimension. These products
are typified by relatively low value raw material sourced from all stages of timber production, are
dependent on the use of glues, generally have superior strength, straightness and stability properties
to solid wood products and are of lower cost than solid timber or alternative building materials.
Australia is currently limited to the large scale manufacture plywood, particleboard and medium
density fibreboard (MDF) and small-scale manufacture of glued laminated timber (glulam), I-beams
and hardboard. Softwood is primarily used in the production of EWP’s because they are a
relatively cheap source of homogenous and easy to process wood fibres and available in large
volumes. Fibres derived from native hardwood species are less used in EWP because of the
heterogenous and less favourable nature of the fibres particularly in terms of the extractives content
and wood density. However, hardwood fibres are used in EWP’s such as hardboard and plywood
(Davidson and Hanna 2004).
Consumption of EWP’s globally has been growing with the increased consumer awareness of their
attributes. In a technical sense, EWP’s generally have greater strength, greater uniformity and
quality than sawn timber and can be used over a wider range of applications. They can also be used
as a lightweight alternative to steel. Compared with solid timber and steel, EWP’s can offer a low
cost solution to the increasing demand for greater performance requirements of the building
industry. The dimensional limitations of solid timber can be restrictive and the supply of large
section timber is declining (Davidson and Hanna 2004).
62
6.3.1 Veneer
The production of veneer can basically be undertaken in two different formats. The first method is
production of sliced veneer, with either a large flitch passed over a knife or the knife passed over
the block to produce veneer leaves, generally in the tangential direction. This style of veneer
production traditionally requires very large blocks (eg. greater than 300 mm in width and 200 mm
in thickness) that are defect free (eg. free of heart, knots, gum veins etc) and sapwood free. The
veneer leaves are mostly glued onto another substrate such as plywood, medium density fibre board
(MDF) or particle board to give the visual impression of solid timber and then used in appearance
applications. With the resource requirements and the reasonable assumption that suitable flitches
can not be produced from hardwood plantation thinnings, sliced veneering is not considered a
viable product option.
The second method of veneer production is through a rotary peeling process. This method is usually
reserved for plywood or laminated veneer lumber (LVL) production, with the difference residing
with the dimension and orientation of veneers in the finished product. Standard rotary peeled
veneering requires log billet of 2.4 metres or 1.2 metres. Historically only high quality logs were
used for rotary peeled veneer production, although as the availability of quality veneer billets has
reduced over time, industry have managed to adapt processes to allow lower grade and smaller
dimension billets to enter the process. Technology is now becoming available that eliminates the
need for spindles to hold the billets during peeling. These splindleless lathes are able to reduce the
minimum peeler core size from 100 mm - 150 mm, down to approximately 50 mm, resulting in
improved green veneer recoveries.
The small trial undertaken in association with Big River Timbers (Section 4.2.4) demonstrated that
it is possible for plantation hardwood thinnings to be processed into veneers and manufactured into
plywood. The log size and quality required however, will probably limit supply to only a small
percentage of the best logs from thinnings. It is reasonable to suggest that the veneering process will
be more suited to the logs produced from plantation final harvest where logs of larger diameters,
longer lengths and higher quality (especially in terms of clear wood) are expected.
6.3.2 Hardboard
The utilisation of plantation thinnings to produce hardboard products is achievable. Trials
undertaken as a component of the study using blackbutt provided very encouraging results (see
Case Study 10). The manufacture of hardboard is limited to a very small number of plants within
Australia. Collins (1999) reported that market opportunities for hardboard products are restricted
due to the ready supply of substitute products available.
6.3.3 Medium Density Fibre Board (MDF)
Medium density fibre board (MDF) production is a possible utilisation option for plantation
hardwood thinnings. The high proportion of sapwood and the relatively low density of the wood
results in a fibre being produced that are more consistent, lighter in colour, and lower in density
than those from the native forest hardwood resource. The former resource is expected to be more
suited to the production of high quality MDF. The high extractive contents compared to softwoods
may still present barriers in acceptance due to the need for additional chemical in fibre preparation.
MDF plants are currently based predominately on softwood forest resources. Laminex Industries,
based near Gympie Queensland, has a 450,000 tonne input per year and blending of hardwood
residue is suggested to be a real possibility. While price is unlikely to be high, the grade
63
requirements for log quality (eg. form and size) would be lower than those of a sawn timber
operation.
6.3.4 Particleboard
Particleboard is unlikely to be a current possibility for hardwood thinnings even though technically
the younger material would likely to be more suitable than older native forest material.
Particleboard has traditionally utilised a softwood resource with no history of hardwood input in
Australia. The main issues are probably the high extractives content and higher density of the
hardwood fibres resulting in undesirable colour and weight as well as difficulties with gluing.
6.3.5 Strand Products
Strand products such as oriented strand board (OSB) and parallel strand board (PSB) could be
options for thinnings from hardwood plantations. These processes are based on lower density
species, typically softwoods, with basic densities of 450 kg/m3 and lower. Currently there are no
strand product manufacturing operations in Australia, although it is understood an engineered strand
lumber (ESL) factory is planned in Western Australia.
6.4
Pulp
The utilisation of plantation hardwood for the production of pulp is well understood and this is the
primary product target for many of the plantations established in Australia. It is interesting that pulp
is one product where plantation grown trees are preferred over mature native forest trees. Given the
higher density of many of the Queensland and northern New South Wales plantation eucalypt
species compared to other areas within Australia, it is predicated that once plantations are older than
10-15 years, their suitability for pulp will decrease due to higher extractive content and high
density. Challenges exist in ensuring economic viability with converting plantations into a pulp
product, with long haulage distances commonly being a limiting factor.
6.5
Wood Plastic Composites
Wood plastic composites (WPC) may be an alternative option for the utilisation of plantation
hardwood thinnings. While the United Kingdom and Europe are yet to fully embrace WPC’s, they
are already well established within the United States of America mainly in the form of garden
decking and non structural building applications such as cladding, exterior window and door
profiles. The USA market was reported to be in excess of USD$350 million in 2001 with
predictions to significantly increase to more than USD$2,000 million by 2011 (Optimat Ltd and
Merl Ltd 2003). WPC product manufacture is not a new process, however, producing extruded
wood plastic products is relatively recent. It is understood that currently there is only one company
in Australia manufacturing wood plastic composite products but they are not utilising eucalypt
wood fibre.
6.6
Bio-energy
Over the years, there has been a great deal of research and effort into the use of biomass as an
energy source and a number of technologies have been developed for biomass conversion. For
example, Horta Nogueira et al (1998: cited in Collins 1999) provides detail of a 30 megawatt
64
electricity plant being constructed in Brazil fuelled with wood fibres, half with wood harvested
from very short rotation eucalypt plantation and half from local pulp and paper plant residues.
The major issues associated with the use of biomass for large scale energy production include:
• Resource mapping;
• Consistency and quality of proposed feed-stock; and
• Matching available resources with power generation technology/facilities.
Traditionally, in high population areas such as Europe and the USA, large centralised conversion
facilities are established and biomass is transported to the facility. High transport costs of low value
biomass will probably make the use of the resource uneconomic in Australia. The use of local
micro-generators can address this problem and has the added advantage of avoiding power losses
that occur when electrical energy is returned to a distant consumer. Another barrier in Australia for
economically utilising plantation material for bio-energy is the availability of other biomass
products that exist in large concentrated volumes (eg. sugar cane residue).
The high moisture content of plantation feed-stock, either freshly felled plantation timbers and or
forest residues, will also affect the economics of using this resource for energy production. A great
deal of energy is expended in the conversion process to dry the feed material and consequently
more in-feed material is required to produce a unit of energy.
While bio-energy doesn’t present a likely immediate utilisation option for plantation thinnings, the
demand to develop economically viable alternative energy sources will no doubt continue to
escalate. Additionally, biomass-generated energy is carbon-neutral providing an attractive
alternative to fossil fuels. This should lead to some new innovative ideas and approaches that may
significantly change the opportunities to utilise plantation thinnings for bio-energy. For example,
Tijmensen et al (2002) reported a process that enables products such as ethanol and methanol to be
produced from biomass and indicated that product alternatives to diesel, kerosene and gasoline may
be possible. Advances in this area may present opportunities for hardwood plantations if feedstock
volumes are viable.
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Case Study 1: Forest Enterprises Australia – Launceston, Tasmania
Compiled from information provided by Tony Cannon and Geoff Pask during May 2006.
Forest Enterprises Australia Limited (FEA) is an Australian Stock Exchange (ASX) listed public
company based in Launceston, Tasmania. The company began as a private company in 1985
focusing on plantation establishment and now has approximately 32,000 hectares of hardwood
plantations under management. Approximately 60% of this is located in Tasmania and is
predominately shining gum (Eucalyptus nitens). The balance is located in New South Wales
(approximately 30%) and Queensland (approximately 10%) and includes mainly Dunn’s white gum
(Eucalyptus dunnii), spotted gum (Corymbia citriodora) and blackbutt (Eucalyptus pilularis). The
company began harvesting their Tasmanian plantations in 1997.
FEA is a vertically integrated company with involvement in a wide range of forest and forest
product areas including plantation establishment, forest management, solid wood processing, wood
chip and log export activities.
In 2002, FEA purchased a HewSaw (see Plate 1), as part of a specialised small log sawmill, near the
Port of Launceston at Bell Bay in northern Tasmania. The HewSaw is capable of sawing and
chipping small logs in a single pass. The sawmill purchase was underpinned by a supply of small
diameter (ie. 120 mm to 270 mm small end diameter) radiata pine logs. FEA saw the potential for
this sawmill to also process similar sized plantation thinnings and clear fall logs from their
hardwood plantations. The sawmill processes approximately 100,000 tonnes of sawlog per year of
which the majority is radiata pine, although, the proportion of hardwood is increasing as more
hardwood plantation areas become available for harvesting.
After several years, a series of sawing, seasoning and machining trials focusing on shining gum
were completed and FEA began producing structural grade kiln dried and dressed timber from this
fast grown plantation hardwood resource. This product is marketed as EcoAshTM (see Plate 1) and
offers sawing and building characteristics that are quite different to traditional resources such as
long rotation pine and native hardwoods. To allow the product to be understood and accepted in the
market place, FEA initiated a testing program on nine to thirteen year old Eucalyptus nitens to test
the timber in accordance with the quality standard, AS/NZS4063:1992. This included bending,
shear, tension and compression testing to determine its structural properties, and its suitability for
building and construction use. The test results were then used to formulate a series of span tables
designed to inform builders and designers about the capabilities of the timber product, including its
span and load bearing qualities for bearers, joists, lintels and rafters. FEA are continuing to trial
EcoAshTM in new applications such as flooring, panelling and furniture manufacturing.
The financial returns for the EcoAshTM product is suggested to be significantly higher when
compared to the softwood sawn timber products produced by FEA and the return gained from the
alternative product option; wood chip, of which FEA export between 200,000 to 300,000 tonnes per
annum.
While the product development work with hardwood plantations has focused on shining gum, FEA
expect to continue this drive for their plantations in New South Wales and Queensland as they come
on line. To date, FEA’s experience processing these species (eg. Dunn’s white gum, spotted gum,
blackbutt) has been limited to the one container load (approximately 12 tonne) of Gympie messmate
and blackbutt logs supplied as part of this project. The supplied logs were scanned and sorted into
66
diameter classes and sawn into various dimensions as illustrated in Tables 30 and 31. The sawn
timber recovered from the study logs has been partially air dried (see Plate 1) but is yet to be kiln
dried and further evaluated for grade quality for products such as the EcoAshTM.
Table 30 Volume of logs in corresponding diameter classes.
Small end diameter
(mm)
120-149
150-169
170-179
180-199
200-222
Sub Total
Reject
(excessive sweep)
Total
Log Volume
(m3)
3.832
1.609
0.885
0.536
0.237
7.099
3.884
10.983
Table 31 Sawn dimensions and recovery.
Sawn Dimensions
(mm)
75 x 25
100 x 38
150 x 50
150 x 63
Total
Green-off-saw Recovery
Sawn Volume Recovered
(m3)
1.237
1.940
0.500
0.096
3.773
53.1%
Plate 1 HewSaw log processing line, EcoAshtm finished product and sawn project timber
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Case Study 2: Richards Milling Company – Rappville, New South
Wales
Compiled from information provided by Greg and Warren Harvey on the 16th May 2006.
Richards Milling Co Pty Ltd began operations in the 1950’s. In 1961 the company moved its
operations to Wyan in northern New South Wales (adjacent to their present day mill) where they
established a diesel powered sawmill. In 1974 they built and commissioned a then “state-of-the-art”
electric sawmill at the location where they currently operate.
In the late 1980s and early 1990s, due to the declining quality and quantity of the available
resource, the company initiated a programme of upgrading their facilities to remain commercially
competitive. In the last seven years this programme has seen significant investments in the
following:
o A log debarking and merchandising line;
o A Vislanda sawline (see Plate 2);
o A Iida planer and associated waste extraction system;
o An additional log loader and forklifts to facilitate handling;
o Upgrades to the logyard and sawn timber storage areas;
o Sawmill building extensions; and
o Construction of a new shed to house the planer and store finished product.
As a result of these investments the company now employs 24 permanent staff and provides
training opportunities for its employees in the use of high technology equipment. The Company
produces a range of green-off-saw products including fencing, landscape, packaging and pallet
material as well as a limited quantity of kiln dried and dressed material.
The Company access both intrastate and interstate markets as well as servicing local markets. It
concentrates on “niche” markets allowing it to respond to market forces rather than being solely
production driven.
Since the commissioning of the new Vislanda sawline production levels have increased steadily. In
2004, approximately 56,000 m3 of log (7,500 m3 hardwood and 48,500 m3 softwood) were
processed. This is well below the full processing capacity of the sawline which has the capacity to
process between 80, 000 m3 to 100, 000 m3 of log per annum on a single shift basis.
The company’s sawmilling operation is based on processing small diameter logs (120 mm to 250
mm SED) sourced from both hardwood and softwood plantations within the region. Softwood log
prices vary between $40.00 and $65.00 per cubic metre delivered and between $55.00 and $65.00
per cubic metre delivered for hardwood.
The success of the Richards Sawmilling Company demonstrates that a viable industry can be based
upon the use of a log resource traditionally deemed too small for sawn timber purposes. The
processing technology used enables flexible sawing patterns even while processing small diameter
logs. The red mahogany logs supplied by this project were processed with no variations to
machinery setup and using their standard sawing patterns resulted in trouble free processing.
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Plate 2 Vislanda log processing line, Richards Milling Company, Rappville, New South Wales
69
Case Study 3: Hurford Family Group of Companies
Compiled from information provided by Lexie Hurford, Assistant General Manager, Hurford Group on 12th May 2006
The Group has grown from a small building construction and supplies firm established in Lismore
in 1932, and is now a third generation family owned and operated business. The Hurford Group
includes the largest privately owned timber company in Northern NSW. Following a disastrous
arson originated fire at the Lismore site in 1979, the group embarked on a massive restructuring
programme that is continuing.
The Hurford Group were pioneers in the development of technologies and processes to convert
hardwood plantation grown resource into high value unique products. Now employing over 200
people within the local area with an annual turnover exceeding AUD$40 million dollars, the Group
comprises:
•
Hurford Building Supplies
o Hardware, paint, timber and builder supplies stores in Lismore and Ballina
servicing the trade and retail markets.
o Hardwood and softwood timber frame and truss manufacture plant in Lismore.
•
Hurford Sawmilling
o Modern hardwood sawmills in Lismore and Casino processing over 40,000 m3 of
logs each year from Crown and privately owned forests. These sawmills were
some of the earliest to be re-equipped to process the current resource of smaller
diameter plantation and regrowth logs.
•
Hurford Hardwood
o Drying kilns and dry timber processing plant at Tuncester, near Lismore. This
facility manufactures and markets high value dressed and profiled hardwood timber
products to local, interstate and overseas markets.
•
Hurford Forests
o Owns and managers forested land on behalf of the Group and other private
landholders. Employs their own foresters to procure resource for the sawmills and
to oversee hardwood plantation establishment for the production of high quality
timber end use.
The frame and truss manufacturing plant began operations in 1973 and now has the capacity to
produce kiln dried hardwood and softwood trusses. Current output is 5% native hardwood and 95%
softwood. The softwood truss feedstock is seasoned, dressed Pinus spp. sourced from various
processors. Approximately 1000 m3 of MGP10 70 mm x 35 mm and 90mm x 35 mm material is
purchased annually for a cost of around $420 per cubic metre. The estimated waste allowance is
5%.
While the Hurford Group has experience in the conversion of plantation hardwoods, the project was
able to supply some 8.5-year-old Eucalyptus cloeziana plantation thinnings with the expectation to
undertake a small trial in truss manufacture. The ungraded sawn timber provided was 70 mm x 30
mm. No difficulties were experienced in gangnail pressing the plantation thinnings material and the
nail holding capability appeared to be above standard. The quality, characteristics and ease of
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handling compared quite favourably with the traditional pine stock. The comment from the
management was that the finished product varied little to the current product in appearance and
weight and therefore would be quite acceptable to the end user.
The Hurford Group would definitely consider substituting their use of pine with plantation
thinnings material providing the grade, length specifications and presentation was to an equivalent
level. Inherent immature log defects could lead to a higher waste factor being experienced so the
delivered cost may need to be lower to compensate. However the small sample provided negated a
rigorous assessment.
71
Case Study 4: Palletmaster – Clontarf, Queensland
Compiled from information provided by Kevin Jackson and Daryl Clarke on the 10th March 2006.
Palletmaster formed in 1984 when Kevin and Audrey Jackson purchased an already established
pallet manufacturing business. Starting with a staff of 10 and a mission to provide a quality product
at competitive prices, they began production of hardwood and softwood crates and pallets to meet
their customer’s requirements.
By 1988, the business had expanded to the stage where they required a larger site. A two hectare
site at Clontarf, on the outskirts of Brisbane was identified and the entire operation was relocated.
The manufacturing process was still somewhat primitive with the products being piece-built,
however, increasing demand forced the exploration for higher productivity and mechanisation. In
1994, an automated machine made in the USA by Vikings was installed which had the capacity to
manufacture 1,500 pallets per day. Demand for Palletmaster’s product continued to rise and the
benefits of the automated machine were recognised, so much so, that an additional 3 machines were
installed, including a computer controlled ‘turbo’ model.
Palletmaster currently employ about 30 staff and produce an average of 4,000 - 4,500 pallets per
day. It is estimated that 99% of the softwood pallets manufactured by Palletmaster are considered
‘one way’, ‘single use’ or ‘disposable’ pallets while approximately 50% of hardwood pallets are
purchased with the intention of being re-used.
The 23rd of December 2004 holds a special memory to the staff at Palletmaster with a company
record of 6,754 pallets being loaded in one day. Palletmaster are considered today to be one of the
largest pallet manufacturing companies in Australia.
Although a ‘standard’ pallet exists, pallet design is dependent on customer requirements and
Palletmaster suggest that they have potentially thousands of different designs with the ‘standard’
pallet design making up only a very small percentage of total production.
Essentially each pallet is generally made up of bearers with a dimension of either 75 mm or 100 mm
high by 38 mm or 50 mm wide. Top and bottom boards are usually either 16 mm or 25 mm thick
and widths of 75 mm and 100 mm are most common (see Plate 3 for example of finished product).
Palletmaster’s preference is to purchase their feedstock already docked to length although
sometimes long length material is purchased and is docked to length on site. This is particularly the
case with softwood bearers where reject or utility grade softwood studs from other organisations are
frequently used. This material is kiln dried, which can be advantageous for some export oriented
pallets, although price is the main driver for sourcing this material. Hardwood is all sourced
unseasoned. The current demand for feedstock is approximately 37,500 cubic metres per year, of
which approximately 50% is hardwood and 50% is softwood. Current buying price for feedstock
docked to length and delivered is approximately $265 per cubic metre for hardwood and $245 per
cubic metre for softwood. Prices of final product vary dependent on design and supply quantity,
however, a ‘standard’ hardwood pallet is sold for approximately $19.30 while ‘standard’ softwood
pallets sell for approximately $17.80.
72
Feedstock grade quality is not high in comparison to many other sawn timber products. Apart from
methyl bromide treatment for a limited number of export pallets, no other chemical or preservative
treatment is used. Timber species is not critical and timber imperfections such as knots, heart (see
plate 3) shakes, gum veins etc don’t pose any real concern to the production of pallets. The three
major grade quality criteria according to Palletmaster are that the boards must stay relatively
straight, want and wane must be absent (or at least very minimal) and have reasonable nail holding
capacity.
Plate 3 Finished pallet product, stock piled feedstock and board quality
73
Case Study 5: Ausgum Furniture – Gympie, Queensland
Compiled from information provided by Chris Pilgram on the 18th May 2006.
Ausgum Furniture is a wholly owned and operated Australian company based in Gympie
Queensland. They produce a variety of Award-winning outdoor furniture manufactured solely from
spotted gum (Corymbia citriodora). The Ausgum Furniture manufacturing plant is one of the most
modern in Australia combining high precision equipment with old-style craftsmanship typified by
the use of mortice and tenon joints and stainless steel fittings.
The Ausgum Furniture Company originally became established in close association, with the
Emerald Sawmilling Company, including sharing premises in central Queensland. The Ausgum
Furniture Company relocated to its current site near Gympie in Pronger Parade after a fire destroyed
the facility at Emerald in August 2003. Gympie was an ideal location for Ausgum as it has a skilled
workforce with consumers and transport infrastructure. The mining boom in central Queensland
made it difficult for Ausgum to attract a suitably skilled workforce due to the attractive salaries and
wages offered by mining companies and contractors.
Since the Emerald Sawmilling Company closure, Ausgum Furniture has been forced to source their
feedstock from other companies. Sourcing suitable quality feedstock at an acceptable price has
proved difficult. At present, between $1,200/m3 to $2,000/m3 is being paid for dried, dressed and
docked to length blanks, with a finished product sawn timber value of around $7,000/m3. At these
prices, Ausgum Furniture are finding it hard to be competitive in the marketplace. Currently
Ausgum Furniture are concentrating on the domestic market; however, in the past they have
exported to the UK, Norway, Egypt, Italy, Greece and the USA.
The dimensions of the furniture components are designed to use smaller end sections, utilising the
strength properties of spotted gum. There current designs utilise end sections that were regarded as
waste, examples of these include 75 mm x 25 mm, 50 mm x 25 mm, 38 mm x 25 mm, 50 mm x
18mm with the longest length being 700 mm. In the whole production process the longest required
length is 2,400 mm.
An average week of production consists of approximately 250 chairs and 40 tables. Depending on
actual design, this equates to between 9 m3 to 11 m3 of timber. Approximately 3,500 m3 of dried
and dressed component blanks are consumed per annum. At present, Ausgum Furniture employ 14
staff; however, this can fluctuate significantly with up to 25 staff required to meet large export
orders.
At present, Ausgum Furniture do not market a natural feature grade product as they believe that it
could undermine the price potential for clearer grades. However, they do see potential for young
plantation grown material as having a marketing edge and suggest an increased level of feature
could be considered.
74
Plate 4 Individual chair components and demonstration chair manufactured from plantation thinnings
75
Case study 6: North Coast Institute of TAFE – Coffs Harbour, New
South Wales
Prepared by Martin Tomasoni, Furniture Design Teacher NCIT
The North Coast Institute of TAFE established a Furniture Design course within the Arts & Media
faculty in 1999 at the Coffs Harbour education campus. The Furniture Design course was initiated
in response to a need identified by regional businesses for training in design and manufacturing of
furniture.
The Furniture Design Department offers students three levels of qualifications; Certificate IV,
Diploma and Advanced Diploma. On average 30 students per year participate in the training
offered. Students undertaking the Advanced Diploma have undertaken three years of study and
graduate with skills & training equivalent to an apprenticeship in the furniture making industry.
The operation of TAFE is to provide quality training and education that emphasises the process of
learning in addition to the development and refinement of designed pieces of furniture. Due to the
nature of the operation the furniture design department does not use commercial quantities of
hardwood and softwood. The total consumption is estimated to be 1 cubic metre of softwood and 1
cubic metre of hardwood. Annually students produce 3-4 small pieces of furniture using a
combination of construction method and materials. The products designed and manufactured by the
students vary considerably. Each design project set by staff requires students to think laterally about
problems proposed, address modern day living styles and trends and redesign what is considered
traditional furniture such as tables, chairs and cabinets (see Plate 5).
The hardwood thinning supplied proved a valuable resource. The imperfections in the ungraded
hardwood thinning did not prove disadvantageous to the processing and manufacturing of the
material. However, we had to select the material to match the structural and aesthetic requirements
for each of the student’s designs. This consideration at times saw imperfections such as heart, and
knots cut out of the material. In addition during the machining process the imperfections in the
material did not prove to be difficult, as knots and curly grain direction seem to machine well.
The TAFE Furniture Design Department would embrace the commercial availability of timber from
hardwood thinnings. However, it was considered that the cost per lineal metre should be lower than
that of traditional (ie. Mature) and regrowth timber. This is due to the value that is placed on the
density, size and features of more mature timber.
In regards to appearance and acceptance by the public, the pieces of furniture made that contained
large laminated areas of knotty thinning were well received and accepted as a natural part of timber
aesthetics. To facilitate greater acceptance by the general public of hardwood thinning in furniture,
marketing of the product should be encouraged due to its sustainable, environmentally friendly
qualities in addition to the structural and aesthetic qualities.
The TAFE Furniture Design Department encourages the responsible use of materials and
passionately support sustainable products within the marketplace. Given that sustainability issues
are at the forefront of design, materials such as the hardwood thinnings have the potential to place a
major role in the industry’s future, focusing on marketplace dictates and desires.
76
In conclusion, it was considered that hardwood thinnings provided a fresh new timber aesthetic and
a feature to hardwood furniture that has long been captured by the softwood market.
Plate 5 Example of furniture designed and manufactured by students using timber from plantation thinnings
77
Case Study 7: Perma-Log – Narangba, Queensland
Compiled from information provided by Warren Jeffrey on the 4th May 2006.
Perma-Log began operations as a privately owned treated timber reseller and lattice manufacturer in
1982. In 1984, the company moved to its present site at Narangba, Queensland and installed a small
treatment cylinder which processed 1,500 m3 in the first year. To satisfy the available demand for
treated pine, a small sawmill and timber machining operation was commissioned, which added
products such as decking and other moulded products to their range. The demand for products
continued to grow and to assist in meeting this demand, a new treatment facility was installed in
1986 and continues to be in operation today.
Perma-Log continued to prosper and in 1990 the operation was purchased by CSR who used the site
as a treatment facility to support their Caboolture sawmill. In 1993, the smaller original treatment
cylinder was converted to allow the use ACQ treatment, making Perma-Log the first plant in
Australia to use non-arsenic, non-chrome, water borne preservative.
In 2000, CSR exited the timber industry and Perma-Log once again became privately owned and
moved its focus back to the predominately wholesale market place. In 2003-2004 a new log peeling
machine, complete with sorting and handling equipment was installed, which increased their
production capacity by approximately 50%.
Perma-Log currently employs 19 permanent staff and a casual base of between two to nine people.
Their annual production ranges from between 27,000 m3 to 32,000 m3 of log with a 51% recovery
rate, equating to between 13,500 m3 to 16,000m3 of shaved round wood products. They mainly
produce a range of treated, shaved round wood poles to the domestic landscape market and are
currently exporting a small volume to New Zealand. They also produce a range of treated split logs,
slabs and wing splits.
Perma-Log’s log specifications require a small end diameter of between 110mm to 220mm and a
large end no larger than 280 mm. Due to transport and handling restrictions, they accept logs in 2.4
m, 3.0 m and 3.6 m lengths. Their standard round wood product range includes 80 mm, 100 mm,
125 mm and 150 mm diameter logs in lengths of 1.8 m, 2.4 m, 3.0 m and 3.6 m. A 4.8 m round
wood product is also sold, but it is not produced on site and is onsold from another producer.
At present, Perma-Log are paying between $48 and $65 per cubic metre (average of $55) for
softwood ‘tops’ and thinnings delivered, although are expecting this price to increase in the near
future. This increase is mainly due to sawn timber sawmills undergoing upgrades to allow them to
process smaller logs and thereby increasing competition for the limited resource. The adoption of a
more direct plantation management regime by Forestry Plantations Queensland (formerly DPI&F
Forestry) whereby thinning operations or reduced or removed will result in less thinnings becoming
available and this is expected to also create a more competitive market for the resource.
Perma-Log have experimented with producing treated round wood products from hardwoods
including plantation thinnings material. While preservative treatment doesn’t appear to cause any
difficulties, the splitting (either end splits or surface checks) that occurs during seasoning is
considered to be the main barrier to consumer acceptance. While it can be argued that hardwood
round wood products may be superior to traditional softwood products in some aspects (eg.
strength), Perma-Log suggest that the current softwood product is performing satisfactory for the
78
majority of end uses. Given this situation, it was acknowledged that for the hardwood plantation
resource to be used in the traditional round wood market, the cost of the resource would not be able
to exceed that of softwood and the processing issues (eg. splitting) would need to be solved.
Plate 6 Splitting in round wood products presents a challenge to utilising hardwood thinnings
79
Case Study 8: Big River Timbers – Grafton, New South Wales
Compiled from information provided by Stuart Austin on the 24th March 2006.
Big River Timbers Pty Ltd is a wholly owned subsidiary of Thos. Pidcock & Sons Pty Ltd which is
owned by fourth generation members of the Pidcock family.
The Pidcock family have been involved in the northern New South Wales timber industry since the
early 1900s. In 1960 the family sold its sawmilling operations and constructed a rotary veneer plant
in Grafton to produce decorative and marine grade veneers. The veneers were sold to other
companies who undertook the panel manufacturing process.
In 1983, due to the loss of the local scrubwood resource through conversion to reserve, the company
changed focus to specialising in form ply production using largely untried regrowth and plantation
eucalypts.
Big River Timbers currently employs 141 people at its Grafton mill and an additional 45 people at
distribution outlets in Brisbane, Sydney, Melbourne, Perth and Townsville. They are one of the
highest value adders in the industry and employ one person for each 335 m3 of log processed. This
is believed to be 2.5 times the staffing of a traditional sawmill.
The manufacturing process at Big River Timbers follows traditional methods and produces both
hardwood (7 000m3/yr) and softwood (14 000m3/yr) plywood products. They have chosen to use a
B-type bond in both the hardwood and softwood panels.
Hardwood logs are purchased in varying lengths from 5.3 m to 13.4 m. Logs are debarked on site
prior to a steaming treatment at 100oC for 13 hours and then docked to the required lengths before
they are rotary peeled.
Big River Timbers have two spindle lathes. The first is used to produce 2.4 m long grain veneers
and will accommodate billets with a large end diameter up to 700 mm and a small end diameter as
low as 360 mm. Lengths between 1.8 m and 2.4 m can be accommodated. The second lathe is used
to produce 1.2 m cross grain veneers and is able to process billets with a large end diameter up to
420 mm and a minimum small end diameter of 260 mm. While Big River Timbers suggest 260 mm
is the minimum small end diameter, this lathe is able to process smaller diameter logs, if billet
quality is suitable (ie. small knotty core and minimal or no end splits); however, the veneers that
result from these billets will usually only be used as low grade core veneers.
After peeling, the veneers are graded, patched and jointed in line with Australian and New Zealand
standard AS/NZS2269:2004 Plywood -Structural. The various grade qualities allow Big Rivers to
make the best use of their resource by allocating high quality veneers to critical section of the board
product (ie. outside or face veneers) and allowing the lower quality veneers to be used in the core of
panel products. `
The glue is applied to the cross bands by twin applicator rollers. The veneers are then stacked in a
pre-press before being hot pressed, trimmed and stacked ready for transport.
Big River Timbers are one of the few plywood manufacturers that will custom make products to
their client’s needs.
80
At present Big River Timbers source all their hardwood resource from regrowth forest; however,
they predict that in the next 8 to 10 years up to 60% of their hardwood log intake could be sourced
from plantations, with a full transition from regrowth forest log within 12 to 15 years.
To ensure that they are prepared for the inevitable transition from their current resource Big River
Timbers are investigating various processing options and new product lines.
81
Case Study 9: Hyne and Son – Maryborough, Queensland
Compiled from information provided by Jamin Tietz, Manager, Hynebeam/ Edgebeam LGL Plant Maryborough on the
17th March 2006.
Hyne and Son began operation in Maryborough, Queensland in 1882 and have developed into one
of the largest and most successful privately owned timber companies in Australia. They produce a
range of products from native hardwoods as well as native and exotic softwoods which include
appearance, structural and engineered products.
In 1978, Hyne and Son began producing hardwood glued laminated beams at Maryborough and can
be considered one of the industry pioneers in successfully gluing high density eucalypt species on
an industrial scale.
Although initially 100% hardwood oriented, it is estimated that hardwood only makes up 6% of the
current manufacturing volume. This equates to approximately 4 m3 per day out of an estimated 64
m3 per day of total feedstock, with the balance being softwood. Although this suggests a reduction
in hardwood usage, the reality is more that the levels of softwood production have substantially
increased compared to that of hardwood reductions due to the restriction of feedstock.
Softwood feedstock is principally sourced from the Hyne and Son softwood sawmill at Tuan with
hardwood feedstock sourced from the Hyne and Son hardwood sawmill at Maryborough as well as
several other hardwood mills.
Grade quality standards for feedstock have been developed in-house for the various products and
are essentially based on high structural properties for the softwood products and Structural Grade 2
in accordance with Australian Standard AS208:2000 for hardwood products.
The Maryborough plant along with its sister plant in Rocklea, Queensland produce a range of glued
laminated beams and edge laminated glue laminated (laminated glued lumber - LGL) beams. Their
main product range is as follows:
• Hynebeam 17C –manufactured at both Maryborough and Rocklea from plantation exotic
softwood;
• Tasbeam 18C –manufactured at Rocklea from Tasmanian oak;
• Hynebeam 21C –manufactured at Maryborough from high density eucalypt species such
as spotted gum, forest red gum, white stringy bark, red and grey ironbark etc.; and
• LGL (Edge Laminated Glued Lumber) –manufactured at Maryborough from plantation
exotic softwood.
While the Maryborough plant hasn’t previously used plantation grown hardwoods, indications from
the testing conducted suggest the strength properties were lower than that expected from the
Hynebeam 17C and perhaps more comparable to that expected from the LGL product. Gluing
presented minimal problems although it was acknowledged that even with the lower density and
extractive contents when compared to native forest timbers, the gluing process would probably need
to follow the traditional hardwood gluing process rather than the simpler process adopted for the
softwood products.
82
Even if strict grade quality rules were introduced, it wouldn’t be expected that the plantation
material would have sufficient properties to use as a direct substitute for native forest timber that is
used in the Hynebeam 21C product.
If the plantation hardwood has sufficient natural durability and can be used in weather exposed
applications, it may also have a competitive edge in certain markets over the standard Hynebeam
17C product which requires preservative treatment, a process some consumers wish to avoid.
However, if the plantation hardwood couldn’t achieve the desired properties to be comparable to the
Hynebeam 17C product, the next product range to consider is the LGL beam range. This sector of
the market is suggested to be extremely competitive due to the availability of other products such as
LVL (laminated veneer lumber). One advantage over LVL may be superior stiffness enabling more
rigid roof and floor structures.
For the plantation hardwood thinnings resource to compete in the same product categories that
currently utilise softwood, the willingness to pay for hardwood feedstock would need to be
comparable with the price of softwood while also taking into consideration the additional process
and handling costs when compared to softwood.
83
Case Study 10: Australian Hardboards Limited – Bundamba,
Queensland
General company information compiled from the Australian Hardboards Limited web site
(www.australianhardboards.com.au). Summary of plantation thinnings trial prepared by Kerry Trenaman, Operations
Manager, on the 25th July 2005.
Australian Hardboards Limited market themselves as being the sole Australian manufacturer of
100% all natural thin hardboards and that Hardboard is the only reconstituted wood panel made in
Australia that is free from added resins and chemicals. Established in 1958, the company now has a
staff base of over 200 employees, a turn over in excess of 30 million dollars and produce
approximately 13,000,000 m2 of hardboard a annum.
The manufacturing process begins with hardwood chips sourced from approximately 100,000
tonnes of hardwood waste (eg. sawmill residue) that is fed through a defibrator that grinds the chip
under heat and pressure into a coarse wood fibre. This is then passed through to a raffinator that
further processes the material into a fine uniform pulp called ‘pulp slurry’. The pulp slurry is moved
along a belt system where water is allowed to drain away. The resulting mat is trimmed to length
and width and enters a press where under great pressure and heat, raw hardboard is produced. The
sheets are further heat treated in ovens to improve the natural fibre bond and water resistance
properties. Sheets are then passed through a humidification process to improve stability before they
are sized, planed and processed further, specific to clients’ needs.
Australian Hardboards Ltd produce a variety of products including shopfitting merchandising
panels (eg. peg board), flooring products (eg. underlay), building products (eg. braceboard) and
board panels (eg. deco hardboard and chalkboard).
Hardboard Production Trial using Young Eucalypt Plantation Thinning
Raw Material Resource
Approximately 50 tonnes of nine-year-old blackbutt plantation thinnings arrived on site during the
period of 27 and 30 of May 2005. This material included the tops of the thinnings and due to the
taper on these logs resulted in generally smaller logs than the process is accustomed to utilising,
both through the chipping operation and the hardboard manufacturing process.
Chip Preparation
The plantation thinnings were chipped on 8 July through the on-site chipper. Table 32 presents a
summary of the distribution of chip size:
Table 32 Distribution of chip size
Size Distribution
Under 6 mm
Over 6mm under 25 mm
Over 25 mm
Plantation Thinning
3.6%
53.6%
42.9%
Average of last 17
Cordwood Samples
5.4%
65.6%
29.0%
The above table shows that the plantation thinnings resulted in generally a larger chip through the
chipping process and it was also noted that there were significantly more ‘slivers’ than would
normally be considered acceptable as feed to the process. The occurrence of ‘slivers’ in the raw
material is detrimental to the chip handling process to the pulp preparation.
84
Hardboard Production Process
The 50 tonnes of plantation thinnings were sufficient to achieve a short duration trial, that is less
than one hour at 100% mix of this material as pure feedstock. There is a period of approximately
one hour either side of this trial period when there is a blending of raw material in the pulp
preparation process.
The hardboard manufacturing trial was conducted by feeding the trial material into No. 1 chip bin in
isolation on the afternoon of 8 July. While the production line was being prepared for the weekend
outage, the afternoon shift made pulp through this one defibrator to fill stock chests 1, 2 and 4 in
preparation for the Monday morning start-up. Approximately 50% of the raw material was
consumed at this time. The remainder of the raw material was consumed on Monday morning at
the demand of the production line. As the plantation thinning feedstock flowed through the process,
less than one hour of production was made with a 100% mix of the plantation thinning. As pulp
demand increased the plantation thinning pulp was diluted with pulp manufactured from general
wood yard feedstock, that is sawmill residues.
No discernable differences were noted during the manufacturing process as the pulp feedstock
moved onto the 100% plantation thinning mixture and moved off again, apart from the occurrence
of numerous interruptions to chip feed resulting from the unacceptable number of ‘slivers’ in the
chip feedstock.
The hardboard manufactured from the plantation thinning mixture was processed under standard
conditions for the product scheduled at that time.
From the estimated 600 sheets made during the period of 100% plantation thinning trial; samples
from each board truck (one in every 90 press sheets) were collected at the end of the process for inhouse laboratory assessment of hardboard physical properties. Table 33 displays the testing results
Table 33 Results of the physical and mechanical tests of blackbutt hardboard
Modulus of
Water
Thickness
Density
Rupture
Absorption
3
(mm)
(kg/m )
(MPa)
(%)
Pallet Divider –
3.18
994
39.6
26.3
Long term Avg
+/-0.13
+/-29
+/-5.1
+/-7.8
+ Std Deviation
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
Sample 6
Sample Avg.
Sample Min.
Sample Max.
Sample
Std.
Dev.
Thickness
Swell
(%)
Moisture
(%)
14.2
+/-3.2
7.10
+/-1.27
2.47
2.60
2.85
2.69
3.00
2.61
2.70
2.47
3.00
946
919
1022
947
975
963
962
919
1022
38.9
35.6
53.5
30.0
48.4
43.0
41.6
30.0
53.5
43.3
52.2
23.1
57.1
27.9
37.9
40.26
23.14
57.06
17.5
19.4
16.5
22.2
16.2
15.5
17.89
15.53
22.18
6.49
7.59
5.31
7.19
5.95
6.50
6.51
5.31
7.59
0.19
35
8.6
13.31
2.51
0.82
Thickness and density are operator adjustable values and the deviation from the norm for the trial
production highlights a set point offset for this portion of the production. The moisture resistance
variables of water absorption and thickness swell are not variables that are operator adjustable and
85
the reasons for deviation from the norm are not understood. If the modulus of rupture had also been
low it would suggest a heat treatment problem but this variable is within normal limits.
The lower than expected moisture resistance values may be raw material related but it is difficult to
be certain with the short production run performed. The impact of specific species on these
properties can also not be eliminated.
The remainder of the production run showed conformance to acceptable physical properties as the
trial raw material was diluted with normal feedstock.
The product that was in production at the time of the trial was selected to tolerate possible deviation
in physical properties that may result from the trial and was therefore treated as normal production
on exiting the production line.
Conclusion
Based on the short trial that was achieved, the young blackbutt plantation thinnings appeared to
perform normally within the hardboard manufacturing process. The concerns with chip sizing and
slivers within the chip feedstock would need to be dealt with if using on-site chipping facilities but
could be addressed by the raw material arriving on site at a size to feed the process directly rather
than as a log.
The lower than normal moisture resistant properties of the trial hardboard remain unresolved and
would need to be addressed in an extended trial when significantly more material was available for
the assessment.
86
7 Conclusion and Recommendations
The potential to use hardwood thinning sourced from plantations grown in Queensland and northern
New South Wales is high and there are a variety of product options to explore. Despite their
different qualities compared with wood from mature native forest resource, their physical and
mechanical properties would enable the resource to compete with softwoods or southern eucalypt
plantations for some applications. In addition, their appearance quality and natural durability could
also reinforce their positive attributes. The latter will need specific studies to assess the performance
with regard to the standards for natural durability and end-users’ requirements for appearance
products.
Round wood products are potentially an ideal product to utilise hardwood plantation material,
especially from early rotation thinning operations. The increasing importance of added-value will
require more research and development efforts in order to reduce the splitting and checking
problems, to adapt suitable assembly systems and to improve sapwood durability by suitable
treatment. The economic model involved in round wood processing and marketing could be the
most realistic.
For sawn timber products, mechanical grading represents a key factor for structural applications
considering the huge variation of wood properties due to juvenile wood and the knotty core.
Grading and sorting will be important to firstly segregate based on known properties (eg. low
density and high density) and optimise the use of the heterogeneous physical and mechanical
properties. The effects of breeding and silvicultural improvements would be expected to improve
the wood quality but the effects won’t be evident for some time. Development of suitable grading
systems will help the industry to transform this resource.
Considering the size of the sawn products, specific engineered wood products should be developed
through targeted studies conducted together with industry. The engineered products should focus on
taking advantage of the asset attributes describe above (ie. structural use with good durability).
Because of the high extractive content of the targeted resource, studies on gluing systems and
procedures are needed to significantly enhance the quality of the final products. The development of
such industry will require much investment compared with other alternative potential products.
These investments will involve specific processing equipment and methodologies along with human
skills training.
A colour and appearance matching strategy is probably one of the most important issues to increase
the value of products arising from young trees. This is specifically true when the raw material is
particularly heterogeneous as in knotty juvenile wood. Natural defects (or characteristics) in wood
are not obviously a systematic downgrading factor for appearance purposes as suitable colour and
feature matching procedures combined with a clever marketing could lend credibility to these
materials.
Probably the most urgent issue that requires immediate attention involves the collection of the
necessary data to allow economic evaluation of each of the product groups. This information does
not currently exist, or at minimum is badly fragmented, but will help to define the best investment
strategies. Two key areas of information that are required to assist in defining the optimum route for
investors are:
87
1. A resource mapping and inventory survey of existing hardwood plantations in Queensland
and northern New South Wales containing important information for market analysis such
as species, plantation area, location, age, growth yield, height and diameter distributions and
global quality of the trees (eg. branching, form and health). Also required is the forecast of
future plantation establishment. This will provide present and future resource availability
information.
2. Better understanding of the wood based products needs (eg. density, piece size, mechanical
and physical property requirements and grade quality) and solid hardwood present and
estimated future consumption. Another critical question to answer is what will be the future
product shortages (including non wood material) and where substitution or revolutionary
products can be sourced from plantations. This will help to define the opportunities based on
end user needs and requirements.
The collection and collation of this information will also provide a clear linkage mechanism
between the ‘grower’ or plantation manager and the product manufacturer or ‘processor’. The
information from the first component will be necessary for the product manufacturer to prepare for
the emerging plantation resource. The information from the second component will be necessary to
allow plantation establishment and management plans to be developed with a clear focus on
economically viable end products. Market niche and alternative product markets could be a first
step in the process of increasing the value of thinnings.
The interaction with industry during the study proved to be very positive with the majority of
participants are eager to continue exploring potential opportunities for plantation hardwoods and in
particular thinnings. This interaction generated a high level of enthusiasm towards many of the
product areas which is encouraging. The enthusiasm and momentum generated through this project
should be capitalised on, with further research and development conducted with industry to pursue
the success of the plantation strategy.
88
List of References
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Standards
Australian and New Zealand Standard AS/NZS1080.1:1997 Timber –Method of Test –Method 1:
Moisture content
Australian and New Zealand Standard AS/NZS1080:3-2000 Timber – Method of test –Method 3:
Density
Australian and New Zealand Standard AS/NZ 1328.1:1998 Glue laminated structural timber Part 1:
Performance requirements and minimum production requirements
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Australian standard AS 1720.1:1997 Timber structures Part 1: Design method
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purposes
Australian and New Zealand Standard AS/NZS2098.2:(1996) Methods of test for veneer and
plywood Method 2: Bond quality of plywood (chisel test)
Australian and New Zealand Standard AS/NZS2098.9:1995 Methods of test for veneer and plywood
Method 9: Procedures for in-grade testing of structural plywood
Australian and New Zealand Standard AS/NZS2269:2004 Plywood –Structural
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manufacture
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groups
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and stiffness evaluation
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British Standard BS373:1957 Methods of testing small clear specimens of timber
91

Utilisation Potential and Market Opportunities for Plantation

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