HR: 0830h
AN: B51D-0995    [PDF]
TI: Global Changes And Tree Growth Rate In The Amazon Forest
AU: * Camargo, P B
EM: PCAMARGO@CENA.USP.BR
AF: CENA/USP, AV CENTENARIO 303, PIRACICABA, SP 13416-000 Brazil
AU: Vieira, S A
EM: SAVIEIRA@CENA.USP.BR
AF: CENA/USP, AV CENTENARIO 303, PIRACICABA, SP 13416-000 Brazil
AU: Trumbore, S E
EM: SETRUMBO@UCI.EDU
AF: UNIVERSITY OF CALIFORNIA IRVINE, 220 ROWLAND HALL, IRVINE, CA 92097-3100 United States
AB: A better understanding of the variations in the dynamics and structure of trees in tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon. In general, tropical forests have been treated as if all trees behaved similarly, and little is known about how forests vary across the large extent of the Amazon basin. Our data show large differences in forest structure, biomass, and tree growth rates among plots under study in three locations in Brazil: ZF-2 Bionte/Jacaranda plots \(Manaus\), Catuaba Reserve \(Rio Branco\), and Tapaj¢s National Forest \(Santar‚m\). These locations span an east-west transect of the Amazon basin with different dry-season lengths. The number of stems $>$10cm diameter and stocks of C in aboveground biomass are the highest in Manaus \(626ha-1, 180.1Mg.C.ha-1\), than Rio Branco \(466ha-1, 122.1Mg.C.ha-1\) or Santar‚m \(460ha-1, 140.6Mg.C.ha-1\). Estimates of mean annual accumulation of C ranged from 1.6 \(Manaus\) and 2.5 \(Rio Branco\) to 2.8Mg.C.ha-1.yr-1 \(Santar‚m\). Trees in the 10-30cm diameter-size showed the highest accumulation of C \(38%, 55%, and 56% - Manaus, Rio Branco, and Santar‚m, respectively\). Our results showed marked seasonal growth, with the highest growth rates in the wet-season and the lowest growth rates in the dry-season. This effect was most evident for trees with diameter $>$50cm. The comparison of the three areas investigated suggests that forests experiencing a longer dry-season have larger annual diameter growth increments for individual trees. Tree average age was larger in Manaus where the increment was smaller. In all the three areas it was found specimens with DBH smaller than 30cm, but with ages over 200 years. It was found a specimen of 17 cm of DBH and age of 920 years. The fact that small trees can reach old ages may alter the scope of the present forest management planning whose focus is tree species of economical interest and the time the take to reach a commercial diameter.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2003 Fall Meeting