Recuperação da biomassa acima do solo em floresta tropical manejada no Vale do Jarí, Amazônia Oriental

Abstract

Managed tropical forests hold large stocks of aboveground biomass (AGB) and may act as a regulator on climate change. Quantification with accuracy of AGB in managed forests requires some attention regarding inventory errors, use of allometric models (local or largescale) and on the exploitation intensity data (local plot) or production unit level (APU). In this study we focus on the uncertainties of AGB estimates generated by these mentioned problems. The data were collected in 15 plots (100x100m) in the management area of the Jari Florestal, eastern Amazonia, Brazil. We evaluated the major inconsistencies of the forest inventory of 8898 trees before and after reduced impact logging (RIL), started in 2003. We used four methods to estimate the AGB a) three with a wood density dependent pan-tropical equation with different ways of integrating the wood density data (obtained from databanks of the Brazilian Forest Service, Jari and Wood Density Database) and b) one local equation. The main inconsistencies found in the inventory were related to identification of species (16.03%) and negative values of tree growth (7.8%). The organization and processing of forest inventory data have improved estimates of biomass. The main uncertainties in the AGB estimates occurred by the choice of the method and allometric model (local or pan-tropical) most appropriate to calculate the biomass. Regarding the recovery of AGB, the analysis showed that the forest can recover their initial stocks of AGB in 12 years after the RIL