Emissão e estoque de carbono do solo sob efeitos de borda e extração de madeira em áreas de floresta na Amazônia central

Abstract

The environmental changes caused by forest fragmentation may affect the forest carbon fluxes and increase the efflux of CO 2 to the atmosphere. The emission of stored soil carbon can accelerate the global warming because of the large amount of soil carbon (138 Gt carbon up to 8 m of depth in Legal Amazon). To understand the edge and logging effects on the forest soil carbon, we analyzed the soil efflux of CO 2 and topsoil carbon stock spatial variation in relation to the edge distances (0-200 m) at ten sites in the Central Amazon. Furthermore, some environmental variables that could explain this spatial variation were measured to get a better understanding of this spatial variation. The complex spatial variation of soil CO 2 efflux is related to many environmental variables as total carbon and free light fraction carbon in topsoil, soil temperature, depth of the litter layer and soil density. The edge effect on soil CO 2 efflux was complex and difficult of be measured, but we find evidences of edge effect increases the top soil carbon stock. Logging without control and during by long time also increases the top soil carbon stock, but increases the soil CO 2 efflux too. These results suggest that despite increase of top soil carbon stock by deposition of vegetal material on soil caused by edge effect and logging, this stock has been decomposed, increasing the soil CO 2 emission to atmosphere.