Aboveground Biomass Estimate for Amazonian Dense
Transcription
Aboveground Biomass Estimate for Amazonian Dense
Mem. Fac. Agr. Kugoshima Uni v., 30.4)-54, Aboveground Niro HIGl'OII·. 1'1')4 Biomass Estimate for Amazonian Dense Tropical Moist Forests Jesus Mardcn dos ~ SA:o.'TOS··. Masaaki (Lunomto,)' o] Forest Receivcd for public.uion and Shigejiro hiA';.'GA YOSIUDA Resources) Septernber 10. 199) Intrnduction The clirnutic changes on Earth hrought on by aurhropic undertaken Bruzilian to ohtain reliahle estirnates of the dcforestation Arnuzon. In ordcr action have motivutcd studics to be rates and uboveground to have a correct undcrstanding biomass in the of the influcnce of the present Arnazonian land-use on the climatic chunges in the world. it is necessary to count on the reliable deforestation-rute data and the estimation of the biornass having thc potenrial to be convertcd into carbon dioxide or other greenhouse Today, controversies gases. over a certain period of time. on the deforestation rate estimates in the Brazilian Arnazon have been lessened after the latest figures of Feurnside ~t al. (t990b). Their works were carried out at INPE (National lnstitute deforestation for Sputial Research) , in Brnzil, with the conclusions rate was 21,21Skm'/year was approxirnately 400.000km'. (1992) presented At the United Nations Environrnental annual defcrestation 17,860, 13,810 and 1I,130km'/year. that the annual during 1978-1989. and that total cleared area (up to 191\9) Conference , Rio-92. INPE rates for 1989, 1990 and 1991 which were , respectívely, This information refers to the Legal Amazon (total area of almost 5 million km') extending beyond the river basin proper (3.9 mil!ion km'J. However, the aboveground, controversies. methods. fresh or dry. biomass estirnates stil! raise a lot of questions and Some estimares come from direct, or destructive methods; and others, frorn indirect Both have suffered severe criticisms particularly because of the aboveground from many researchers around the world, dry biomass estimares derived from the different sources which are variable. Nearly all of the estimates forest inventories obtained based on indirect methods depend on information made for harvesting by using wood density purpose only. Also, the volurne-based (rnean value for all Amazonian derived from estirnates tree species at dbh), are and a correction facto r for trees with dbh smaller than 25cm. The most recent estimates of Brown and Lugo(t990) , based on inventories (Food and Agriculture Organization) made by FAO experts during the fifties and sixties in the whole Amazon areas, vary from 90 to 397 metric tons per hectare, with a weighted average of 268t/ha. Cl99ll pointed out that Brown and Lugo's(1990) 290t/ha. Fearnside Their first estimare (t 987) concluded was 155t/ha Fearnside weighted estimare is now closer to his own, for dense Amazonian that the best estimate for aboveground • National Institute for Rescarch in the Amazon, Brazil ([NPA) •• National Institute for Spatial Research, Brazil (JNPE) forests. On the other hand, dry biomass in the Brazilian Niro HIGI'CHI, Jesus Mardcn dos SASTOS, Masaaki I~IASAGA and Shigejiro YOSHIDA ./l . . RORAIYA ~oavlsta . __ : ..'_.~. o' \ AIIUA ' Y·anau·s... o' "~ \ ; • Belé. . I ROHOÔHIA :tr:/~.'''''''-''''' .'...~. 8rasllla ..- •.•.•••• ~.J. r·-... ~ -'. STATE 30' 30' 40' 60' Fig. 1. Amazon was 215t/ha(S.D.=61.7), Legal Amazon in Brazil. based on data from 13 inventories rnade by FAO experts. Direct rncthods involve the felling and weighting of ali the trees in an fixed-area sarnple plot. Brown et aI. (1989) have pointed out that this rnethod usually produces unreliable estimates on account of their relying on data from sarnple plots that are too small, too Iew, and often selected with bias. l3ased on literature, estimates from direct methods vary frorn 330 to 550t/ha (Brown and Lugo , 1990). Fearnside's (1990a) estimates vary from 155 to 61Ot/ha for the same Amazon region, Klinge and Rodrigues's (! 973) study is one of the most frequently Amazonian biornass. Their study, conducted dry biomass estirnate of 400t/ha, cited with respect to at a site near Manaus, Amazonas State , revealcd a based on a 0.2 ha plot. At a spot situated not v.:ry far from this site , researchers from INPA (National lnstitute with almost the sarne figure, approximately Lescure et aI. (1983), the aboveground for Research in the Amazon) and INPE came up 400t/ha (results not yet published), dry biornass estimate According to for forests in French Guyana is 570t/ha. Feurnside í 1987) proposed 254.5t/ha as a conciliatory aboveground dry biomass estimate for the Brazilian dense tropical moist forests. One thing that these two approaches share to some extent estimare for Amazonian forests using direct measurements it is necessary to improve the indirect methods before obtaining We conducted a forest inventory directed at estimating the data were collected according to the previous weight of trees with different dbh and total heights. is that aboveground biomass is almost impossible. For this reason, reliable estimares. standing instructions aboveground biomass, and fixed on how to obtain the fresh Aboveground Biomass Estimare for Amazonian Materlals Dense Tropical Moist Forests ~5 and Melhods 1. Mathemutical ~Iodels In temperare standing Iorests. aboveground lhe different mainly in the United biomuss is a routine States, pracrice rnodels which have been tested, lhe use of mathernatical rnodels with a high levei of refinernent. lhe allornetric equations 10 esrimate According to 1I1 and (2) have shown lhe best results. where: W =fresh W=a' dhh" W=a' (dbh • ht l" or dry weight dbh =diarneter ht =total at breast height height a and h = regression coefficients In the tropical rnoist forests. especially forestry literature, French Guyana. of lhe development Lescure in lhe Brazilian Amazon. there are no records, in of malhemalicalmodelsusedloestimalehiomass.ln et al, (Jl)~3) used lhe allornetric equation to fit their observed hiomass data. One of lhe rnain obstncles has been that it is lhe tirne-consuming fit of lhe data 10 natural for this kind of initiative. barrier hypothesized models, In Ihis study, aboveground Brnzilian Amazon: Tucurui, Department of INPA. experimental station, in Tahle Data biornass Xingu, Moreover, Sarnuel by lhe Tropical 50km north of Manaus. and Balbina Forestry The descriptive statistics as well as lhe of Arnazonian data carne from lhe following Babaquara. collected data collection species diversity different + collected Department forests regions cnrne 5lO0C<ZOcm ;;:2Oom OC N WF O H Min Ma. Mcan 102.3 S.O. 125.8 3.8 WF 257 9.1 6S0.0 O 257 'J.6 257 5.U 1.3 I'J.R H 2SA 13.6 4.6 WF 113 157'JR.0 1926.6 2+18 O 113 112.5 2U.O 16 113 10.1 120.0 38.0 35.3 H 25.0 6 =diarneter classes = nurnber of stems = fresh wcight in kg =diameter at brcast height, total height in m = N 1.3m. in cm from an of those dat a are presented Table I. Descriptive statistics of lhe dai a used in developing mathematical rnodels for aboveground biornass Variablc in lhe by lhe Botuny I. OC is a 46 Niro HIGL:Oil. Jesus Marden dos SA~TOS. Masaakí IMASAGA and Shigejiro YOSHIDA The following regression models for biomass estimation were tested: W=a' O' (3) W=a' (O· H)' (.I) W=u+b ' O+C· O' (5) w=n+b : H+c' O'· H W=a . O' • H' where: W =total O =dbh (6) (7) (trunk and crown) fresh or dry weight in kg (dinmeter at breust heighr) in meter H =totul height in meter a. h. c = regression cocfficients According to Santos (J <)92) the biornass rnodel used in eguation (7) produced the best results for both of thc diarneter classes. S~dhh<2()cm linearizcd, and for trees with dbh~20çm. using natural log: and the ordinary least squares unalysis. This model hud the lowcst standard coefficient, and the best residual distribution. error method of estimare. This equation was was used for regression the highest determinarion The surnmary of this result is presented in Table 2. This rnodcl has been used quite often to estimare the volume of Amazonian forests. Table 2. Results of regrcssion analysis in euch diamercr class Coefficients DC a b 5:O;dhh<20cm -2.4768 2.2301 dbhs:2Ucrn -3.8101 1.4631 R' S.E. U.6518 U.97 U.2451 1.8190 U.92 0.3728 R' =deterrnination coefficient S.E. =standard error of estimare 2. Forest Inventory Systernatic Amazonian sarnpling rnethod dense forests. characteristics, was used In each sarnple according unit, 10 Higuchi's (1986-87) the following information the cornrnon narnes of tree species, and lhe independent findings for was taken: site variables dbh and total height (10% of trees observed in each sarnple unit) , The sample unit shape was rectangular, et al. (1982) for inventories established. 20 by 200m or 4,OOOm'as recommended in Amazonian Within the sub-sample, forests, Four sub-samples by Higuchi of 20 by SOm were 10 by 10m was established 10 measure trees with dbh counting less than 20cm, 3. Regions covered by lhe foresl invenlory O) South of Pará Marabá is the reference town in this region, Pará State) , and about 2,ooOkm east of Manaus predominant about 600km south of Belérn (Capital of Amazonas State}. (Capital of Big farms are in lhe area. The forest inventory was carried out in seven different localities of the region. These localities and the nurnber of sample units in each point are presented in Table 3. •• o :!:: -e Abovcground Biomass Estimare Table 3. South of Para -locnlirics point for Amnzonian Dense Tropical Mois: Forcsts """1'1<-" und thc number of sarnplc unirs in euch S.U. Lnt.:aIIlY caSlrAR Pioneira Farrncr. IUOkm SW Marab,', Carujas. Enviroumcntal Tapirapc 45km SW Maraba CVRD. 45km SW :'laroo" Forest Reserve. lron Mining. . .jj)km SW :.taraoil CaSIPAR. Sao Jose Farrner. 4. Prorcction. Carujás. Biological Reserve. Tapirapé-Aquiri Nationul IIXlkm SE Maruba Carujás. ItXlkm SE ~Iaraha IIXlkm SE ~brah" Forest , Carujús. 57 S.U. =nurnhcr of sarnplc units This area with a signitican! "castanheira" fact , rnost of the forcsts and logging. Amazon. converting The speed of this conversion have been closed because to srnoke, by pasture provoked transportation on the unpaved The nurnber to Verissimo roundwood. were Today, however, the situation for instnnce , rnany from the tirnber is also irnpressive. According consumed for those prograrns. of the 1990s it was expected products on the PA-150 highway) approximately 400.000m' of ali the timber-oriented and these consurned , of industries of along the Belem-Brasiliu alrnost 3 million cubic rncters et al.. 1991l. Toduy, more than one hundrcd tree in this region. had functioned has been value of forest these mainly of subsidized the beginning inverted. only as sub-product agriculture of other and cattle Forest products are When federal subsidy programs that deforestation maintained developrnent ranching now being programs. used were discontinued as in rates would begin to be decreasing. it at the sarne leveI. South of Rorairna Caracarai is the reference (Capital cattle in the Brazilian in the air, due either or to dust (300km NE of Marabá, by forest industrics consisting of rnainly sawrnills, and in operution in 1990 (Verissirno subsidies (2) preparation, particles 200km north of Marabá. (about indispensable but the increased of pollutant the total consumption Up to the 1970s, forest activities in the region, During the dry seasou, area consisting in operntion. represents species are being processed into other land use forms are: mining. is impressivc. or agriculture there were 238 sawmills projects forests rate in this region is one of the highest in 1991. InParagorninas annually prior selectivc roads. in Tailandia This volume the State of Amazonas of roundwood of the fact that they have suftered as highway. In or "mogno". of the large amount of forest industries, et aI. ((989), in 1989, 48 sawmills highwayl natural The deforcstation excclsa), locallv known partiallv conserved along the PA-l50 (S ••.ietcnia macrophvllu) The main acrivitics airports ot "brozil-nut"'l1al/zo//ctia look intact irrespcctive logging of "rnahogany" ranching presen.:e represents the last furcst reserves of State of Roraima) town in this region, situated about , and about 700km north of Manaus. 150km south of Boa Vista Small farms are predorninnnt in the area. The forest inventory and the number municipalities: Norte", of sample Caroebe, BR-2\O highway. was carried out in three different units in each are presented localities of the region. These localities in Table 4. This work covered São João da Baliza, Sao Luiz do Anauá e Caracarai-along the following the "Perimetral ~s Niro HtGl:CHt.Jesus Marden dos SASTOS.Masaaki hlASAGAand Shigejiro YOSHIDA Table 4. South of Roraima-sampling points and the number of sarnple units in each point s.u. Locality Caroebe, Lote Sr. Joaquim. 200km SE Boa Vista Sáo João da Baliza. Lote Sr. Oliveira. 200km SE Boa Vista Sao Luiz do Anauá . 150km S Boa Vista 20 20 17 57 Total S.U. = nurnber of sarnple units type vegetation (forest The landscape is dorninated by secondary forests, or some "Campina" on white sandy soils) , ano is scattered with primary dense tropical moist forests. This region is labeled qualifico as a high risk area for deforestution. colonized since 1<)70saccording to the traditional Colonizution ano Agrarian Reorgunizution) region was the participation average) programs . The peculiurity of the Stute Governrnent. of INCRA because it has been (National of the colonization lNCRA Instituto for process in this gives a plot of land (50ha in to farrners coming from elsewhere in Brazil, They irnrnediately cut down the forest to guaruntee Iano tenure , and burning is the only process tuken by thern to prepare the areas for plantation. Sirnultaneously with the State Government's production zone of Roraima failed. In addition, reduction of its participation the clirnatic conditions, adequare technical assistances ano the high living costs have contributed holders have insisted on pursuing their survival Ihrough agriculture, another "eldurado", to the failure. Many srnall and some have shiíted In south of Roraima, logging is still n secondnry activity, or a sub-product of clearing for projects, Only smnll sawmills with totally obsolete equipments The following tree species are lhe mostly used ones: "angelim pedra" excelsai , "cardeiro" to some being now gold rniners in Roraima. agriculture and other development are operating. lhe agriculture tropical diseases, lack of (Scleronema micranthumt garncla" tNectandra rubrai , "piquia" , "cedrorana" (Aspidospermll (Dinizia (Cedrelinga cateniformis) , "louro sp.) and "sucupira" (Andira sp.): 4. Additional inforrnatlon (t) Floristic cornposition A floristic survey was carried out at lhe sarne lime as lhe forest inventory. This was done by researchers from lhe Departrnent separately, of Botany of lNPA, and lhe final reporl is going to be presented For the forest inventory purposes eommon names of tree speeies or morpho-species were used. (2) Morpho-species abundanee and frequeney This inforrnation is presented to determine inventoried regions. For a better understanding done by Department (3) lhe dorninant Iree speeies or morpho-species in lhe of lhe forest structure of those regions lhe work of Botany is more appropriate. Fresh and dry weight ratio Fresh and dry weight ratios were determined at the Tropical Silviculture Experimental from data collected in lhe Biornass Project area, Station of lNPA, SOkm north of Manaus. Samples from trunk , branches, leaves and flowers or fruits were dried at 105 degrees Celsius until weight stabllity was reached. Preliminary results show that lhe total dry weight represents an average of 60.4 % of the fresh weight (N=76 trees and S.D. =7.8). Also, lhe trunk weight represents 68.6% of lhe Aboveground Biomass Estimare for Arnazonian Dense Tropical Moist Forests total tree weight (N=76 and S.D. 49 = 14l. Results 1. Diomass equation The best equations for estimating standing aboveground In WF=-2.4768+2.2301 In WF= -3.8102+ where: WF=fresh 'In(D) fresh biornass are as follows: +0.6518 'In(H) (5:;;;dbh<2Ocm) 1.4631 • In (O) + 1.8190 • In (H) (dbh~20cm) weight in ton Fresh weight is usually more dependem on the total height than the dbh of a tree. Therefore, the previous model produced the best results. In addition. according to Gillespie and Cunia (1989) n:odels not including pararneters. height .IS an independent variable, produce biased particulurly when data collection is based on the proportional estimares of the probability to the tree size. 2. Aboveground biomass estirnates The results of the forest inventory for the South of Para and the South of Roraima are summarized in Table 5. Visually, one has the irnpression that Iorests in Pará are higher than those of Rorairna because of the significant presence of the huge "brazil nut" trees, However, not confirrned by the inventory. The forests inventoried in Rorairna presented this was a rnean basal areu, per hectare. being 30% higher than in the Pará ones, as does the aboveground biomass. On the other hand, Para forests are likely to be more hornogeneous since the coefficients of variation for number of individuais per ha (N). basal area per ha (BA) and fresh weight (WF) pararneters from Roraima were always greater than those of the Para ones. Table 5. Estimares on hectare basis in each inventoried region South of Para 5;S;O<2Ocm O;;:2Ocm 131 1027 N BA (m') 16.26 7.60 Mean WF (ton) 227.27 values 79.53 WF (ton) 48.04 137.27 26.1 30.5 N Coefficient 32.3 43.7 DA of variation 47.0 WF 36.0 59 350 N DA (m') 2.64 6.39 Minimum WF (ton) 26.04 75.20 1800 220 N BA (m') 13.44 44.32 Maximum WF (ton) 148.80 584.24 N =number of individuais BA =basal area in m' WF =fresh weight in ton WO =dry weight in ton Variab!e Ali 1158 23.92 306.80 185.31 27.9 31.6 35.6 495 10.81 115.32 1978 50.05 636.64 South of Roraima O;;:2Ocm 5:o0<2Ocm AI! 1096 168 1264 11.15 20.87 32.0~ 377.36 134.61 242.75 81.30 146.62 227.9~ 35.3 37.3 22.6 41.7 44.7 43.7 41.1 46.0 42.9 60 490 350 3.61 7.20 15.11 42.23 86.23 184.79 23-17 2250 280 23.30 319.39 45.92 495.04 58.39 643.32 Fresh weight (WF) estirnates for South of Pará and South of Roraima (for vegetation with 50 Niro HIG\XHI. Jesus Murdcn dos SA~"OS. Masaaki dbh;;: Sem} are as follows. respectively: WF=30ó.SI/ha íSouth WF=377..lI/ha Dry weigh: dbh;;:5em) (WD) estirn.ues of Para} (South of Roruirna l for South of Par.i aud South of Roruima (for vegeturion with are :IS Iollows, respectively: A sirnple camparison WD=lliS.31/ha (South of Pará) WD=227.91/ha (Sourh of Rorairnal af these estimares Dry wcight estirnates of this work. estimare (19li7 ) • 25~.51/ha. of Fearnside 10 that of 2ISI/ha. these estimares However, this comparison ali estimares In this 10 facilitate Brazilian with orhers obtuined IS5.3t/ha and 227.Yt/h:l. carricd are. is nOI quite relevam. 10 lhe conciliutory froui Brown and Lugo (I Y90J. or out by FAO expcrts (Fearnside. using lhe sarne diarneter Iorests elsewhere <Ire comparable and 10 Ihal of 26ô'i/ha based on 13 inventories were obtaincd. of Pará and of lhe Roruima carried l~lA~AGA and Shigejiro YOSHIDA 19S7J. Ir ali class limits. lhe dry biornasses of lhe South respectively, 2~% and li% smaller thun lhe others. does not muke much scuse because thc mcthodologics uscd 10 obtaiu vary gre.uly evcn for datu collectiou. the number SIUU)' cornparison Amazon. lnvcntories out by FAO experts pcr ha anel the busal of individuals arnong differcut forest invcntories carricd out in different are presented arca per ha, were also estimatcd which have been carried localities in lhe Arnazon. those in Tablc 6. Table 6. Mcan valucs estimares on hectare busis in differcnt in the Brazilian Amazon {dhh;;::2ücm} Locality out in thc excepting N DA (ndha) localities Source Trombetas 171 23.0<) Ri" Arinos 119 13.58 INPA/CPST. PIC Altamira 146 :21.97 UFPr/CPF. INPA/CPST.19S:2 1983a 1976 UHE Balhina 191 ~'I.3X INPA!CPST. 19S3h EEST 254 22.74 INPA!CPST. s/d 19S3 UHE Santa lzabel 131 15.22 INPA!CPST. PDRI/ Acre 135 17. 7~ INPA!FUNTAC. Taking inta account only lhe dhh;;:2Ocm c1ass. lhe estimates 1%9 for the N and DA variahlcs are as follows: N = 131 trees/ha and BA = 16.26m'/ha (South of Purú) N = 168 trees/ha and DA = 20.87m'/ha (South af Rorairna) In the Sauth of Pará. N and DA estirnates localiries inventoried are 20% smaller (Table 6), while those are greater Ihan the average UHE Santa Izabel (only BA). This rneans, on the sarne comparison potential However, of the South of Pará regian is srnaller than lhe average Sauth of Rorairna The difference is within the Arnazonian of 2~ % in lhe aboveground basis, that the quantitative af lhe most Amazonian (19li7) is better by this wark in comparison understood, South of Pará region. Since N and BA are 20% smaller than the Amazonian to have the sarne difference in terrns of biornass. In camparing the estirnates af the dry weight obtained with the results frorn direct method the difference forcsts. average. dry biomass estimated with those of Drown and Lugo (1990) and Feurnside of lhe seveu than it anly in relation to Rio Arinos and in this survey, is quite high and difficult concerning lhe average, it is expected ISSt/ha 10 und 228t/ha. be explained. These Aboveground estimares Biornass Estimare are in the inferior (Feamside, Arnazonian for range for Amazoniau Dcnse Tropical Iorests. Moist Forests which is from 155 to 610t / h" 1990a), This difference can partially be explained by the distinct rnethodologies in both the rnethods, Direct rnethods have to be applied more extensively the Brazilian Amazon, with more replicates feeding back the current mathernatical in different regions are presented aboveground models used to estimare the standing aboveground biornass. and lcuves) in Table 7. Trunk has the biggest participation for both in the total biomass, reaching alrnost 70%, while leaves contribute to it with only.j%. of information cornpartrnent is importunt behaves This typc because when fire is used to prepare the land for plant.uion. differently. in and larger sampling plots, mainly for the purpose of Mean values of the fresh weight of the cornpartrnents ttrunk. brunches inventoried uscd localities In general. the leuf biomass is totally burncd during each the first burning. while less than 50% of the trunks are burned. Tuble 7. Mcan valuc estirnutcs Rcgion of fresh wcigh: in each trce compuruncnt South of Para Trunk Brunchcs Lcaves South of Roruirna (rnctric ton pcr hectare) D~2t"l1l Ali 5:óO<21"m Cornpartment 5~.5ó 155.~1 2IUA/) 21.63 ei.s; Y.5~ S3A5 3.3~ 12.S') Total 7~.53 ~~7.:'7 30ó.XO Trunk 92.35 166.53 25X.SX Branches 36.61 66.02 102.63 Leuves 5.65 10.20 15.S) TOlal 13~.61 2~2.75 377.36 3, Abundance and frequency The nurnber of species, for forest inventory purposes, rneans 'individual, grouped or rnorpho species. Eaeh inventoried region presented figure quite well represents Arnazonian 250 different species with an overlap of 70%. This forests, Taking into aeeount only trees with dhh ~ 20em, 32 species (or rnorpho-species) more than 80% of the total individuais following speeies (Burceraceae) are the rnost , "pau-pretinho" sarnpled frequently (Legurninosae}, in both the regions. observed and abundant: "inga" (Leguminosae) (Sapotaceae) ,"matamata" (Lccythiduceae) .vbreu-verrnetho", the "breu-vermelho" and "giro" (Meliaceue) - which are not actually sold in the region. In South of Rorairna the most important "abiurana" represem In South of Para, species are: "faveira" (Legurninosae) and "inga", For the diarneter c\ass "between 5 and 20cm" (S:;;;dbh<20) ,25 species represem 80% of the total sarnpled individuais. abundanee and frequency different botanical In South of Pará the most important are:"branquinha" families, "inga", South of Roraima the rnost important (Sapotaceae) , numerous "breu-vermelho" and "joao-rnole" species are: "abiurana", more than species in terrns of species of lianas from (Chrysobalanaceae l. In "breu-vermelho", lianas, "envira" (Anonaceae) , "inga" and "matamata". The most valuable speeies in the South of Pará is "mogno" or "mahogany" abundance in the inventoried sarnpled (13 trees in each regeneration (Meliace l , but its region is quite insignificant. Only 3 individuais were found in 22.8 ha 100 ha) for dbh;;: 20cm class, and there is no record of natural or for 5:;;; dbh<20cm class. On the other hand.rcastanheira" or "brazil-nut" I I 52 Niro HIGUCH1. Jesus (Leeythidaeeae) Marden is very important dos SA~TOS. Masaaki to the forest strueture IMA:<AGA and Shigejiro YOSHIDA at least in the dbh~2Ocm c1ass. Thirty one individuais were found in 22.8ha (more than one tree per ha) • and it was found in almost 90% of the sarnpled plots. However, natural regeneration is almost absent. Discussions For the South of Para and the South of Rorairna estimares of 185t/ha and 228t/ha. respectively, regions. the dry aboveground biornass for ali the vegetation with dbh greater than 5em. are quite reliable, because they come from forest inventories carried out exclusively for biomass estimation, within a limit of error smaller than 10%. The basal area estimares are 23.9m'/ha and 32.0m'/ha. respectively for South of Pará and South of Roraima. From a quantitative point of view, the aboveground biomass estimares of the inventoried íorests are smaller than the Amazonian averuge. However, it is quite important to point out that the inventoried forests do not fulfill the profile of primary Amazonian forest. Most of the South of Pará forests, for instance , have been submitted to a prior high selective "mahogany" harvesting even in the protected forest reserves. The sarne can be said of the South of Roraima forests where the only difference lies in respect to the tree species harvested earlier. Nevertheless. these forests represem the "most" virgin stands in these regions. There is no doubt deforestation, deforestation about these two regions of the environrnent. are seriously threatened They have presented by the highest rate in the last five years, and probably will rnaintain this rate for some time. still. The speed of the transformation development the fact that followed by the degradation principies from forests to other land uses is irnpressive. Any sustainable have not been considered yet by most projects in both the regions, Compared to other portions of the Brazilian Arnazon, these inventoried regions have good access, at least in the form of six hundred kilometers of paved road. Forest activities are also intensive principally in the South of Pará. Based on the number of sawmills in operation in this region it is probable that forest products are economically of not a small interest. This means that farrners do not burn ali existent biomass when they are preparing areas for plantation. For this reason, the amount of gases finally released to the atrnosphere, due to lhe burning can not be taken as a due to the biornass estimates of the original forest.So, the information from this work is important to calculate the biomass of Amazonian forests which has been transformed into other forms of land use, but the estimates of the amount of gases released to the atmosphere will require more specific studies. Summary The making of a forest inventory aboveground biomass for Amazonian was carried out exclusively to obtain an estimate dense tropical moist forests, particularly of in the South of Pará and South of Roraima. These regions hnve suffcred excessively high deforestation rates in the last five years. Aboveground biomass wns estimuted through mathernatical and crown) fresh and dry weight of whole vegetation with a diameter counting greater than Sem. The selected rnodel contained biomass, this also presents estimates models for total (stern at breast height (dbh) tree dbh and total height. Besides for number of trees and basal area on a hectare Sampling size was 22.8ha, and plot dimensions basis. were 20 by 200m for both regions. Dry weight estimates for South of Pará and South of Roraima are 18St/ha and 228t/ha, respectively. Aboveground Biornass Estirnate for Arnazonian Dense Tropical Moist Forests 53 Reference I) Brown, S.• A.J.R. Gillespie and A.E. Lugo: Biornass estirnation methods for tropical forests with applications to forest inventory data. Forest Science, 3S (4),881-902 (1989) 2) Brown, S. and A.E. Lugo: Biomass Estirnates Amazon.25pp. (1990) for Tropical Moist Forests of the Brazilian 3) Fearnside, P.M.: Summary of progress in quantifying the potential contribution deforestation to the global carbon tropical ruin [orests: Problcms problern. Workshop proceedings for research (USP/CENA. of Amozonian biogeochemistry 01/ of Piracicaba, Brazil) , 75-82 (1987) 4) Fearnside, P.M .. M.M. Keller. N. Leal Filho and F.M. Fernandes: Rainforest burning and the global carbon budget: Biomass. combustion . Amazon. 2-1pp. (1l)'.IOa) efficiency and charcoal formation in the Brazilian 5) Fearnside. P.M .. A.T. Tardin and L.G. Meira Filho: Deforestation INPE/INPA. rate in Brazilian Amazon. Spp. (19l)Ob) 6) Fenrnside , P.M.: Forest biomass in Brazilian Amazon: Cornrnents on the estimate by Brown and Lugo. lntcrciencia 7) FUNTAC/INPA: AC. Technical (in press) Inventário Report. florestal e diagnóstico da regeneração natural da área do PDR!/ 151pp. (1989) (in Portuguese with English surnrnary) 8) Gillespie, A.J.R. and T. Cunia: Linear regression models for biomass table construction, c1uster sarnples. Can. J. For. Rcs .. 19.6(,,;·673 (1989) using 9) Higuchi. N .. J. dos Santos and F.C.S. Jardim: Tamanho de parcela amostra! para inventários florestais. ACIll Amazonica, 10) Higuchi, N.: Amostragern de terra-firme. 12(1).91-\03 sistemática (l982) (in Portuguese with English surnrnary) versus amostragem aleatória em floresta tropical úmida na região de Manaus. Acta Amazonica. 16-17(unico), 393-400 (1986) (in Portuguese with English summary) n) INPA/CPST: Inventário florestal no Rio Trombetas. Technical Rcport, 49pp. (\982) (in Portuguese 12) INPA/CPST: INPA/SHELL-ALCOA. Inventário florestal da UHE Santa Izabel, Convenio INPA/ELETRONORTE. Technical Report, 4lpp. 13) INPA/CPST: Convenio with English surnrnary) (\983) (in PORTUGUESE with English summnry) , Inventário florestal-projeto do Rio Arinos. Technical Report, 64pp. (1983a) (in Portuguese with English surnrnary) 14) INPA/CPST: Invent:irio Technical Report, !llpp 15) INPE: Deforestation environmental florestal Balbina. in Brazilian Amazon. Convenio INPA/ELETRONORTE. with English surnrnary) Poster presented during the United Nations conference , Rio-92 (1992) 16) Klinge, H. and W.A. Rodrigues: ae« da UHE (\983b) (in Portuguese Yenezolana, 24.225·237 Biomass estimation in a central Amazonian rain forest. Acta (\973) 17) Lescure, J.P .• H. Puig, R. Riera, D. Leclerc, A. Beekrnan and A. Beneteau: epigee d'une foret dense en Guyane Francaise. Acta Ecologica/ Ecologia La phytomasse Generalis, 4 (3). 237-251 (\ 983) (in French with English summary) 18) Santos, J.: Equações Dissertação 19) UFPR/CPF.: de biomassa para a floresta tropical úmida da Amazonia de Doutor pela UFV (in progress) , Personal communication Inventário florestal do PIC Altamira. Convenio Report, 129pp (\976) (in Portuguese with English surnrnary) 20) Verissimo. A .• M.M. Manos, Z. Brandino, C. Uhl and I.C.G. Brasileira. (1992) UFPR/INCRA. Vieira: Impactos Technical sociais. « 5~ Niro H1GUCHI.Jesus Marden dos SA.'lTos. Masaaki economicos e ecológicos da exploração Arnazonia oriental: o caso seletiva de Tailandia. l'lA:-<AGA and Shigejiro YOSHlDA de madeira numa região de fronteira Pará Desenvolvimento, 25, 95-115 (1989) na (in Portuguese with English summary) 2I) Verissirno, A., P. Barreto, madeireira e perspectivas M.M. Mattos, R. Tarifa and C. Uhl: Impactos para o manejo sustentá vel da floresta Amazonia: o caso de Paragominas (in press) (in Portuguese da atividade numa velha fronteira with English sumrnary) da