资源环境科技发展态势分析平台

Forests in southwestern Amazonia are increasingly being converted for agriculture, mining, and infrastructure development; subjected to low-intensity selective logging of high value timber species; and designated as conservation areas and indigenous reserves. To understand the impacts of forestry in this region, we evaluated carbon emissions from felling, skidding, and hauling in five FSC-certified concessions where workers were trained in reduced-impact logging (RIL) and in four non-certified concessions where workers were not trained in RIL in Madre de Dios, Peru. Emissions estimates did not differ by certification status, so we established a single baseline for selective logging emissions. Total carbon emissions from selective logging were low per hectare (4.9-11.6 Mg ha(-1)) due to low logging intensities (2.9-8.1 m(3) ha(-1)). Despite the unique architecture of trees in the southwestern Amazon (short stems and large crowns), emissions per volume and per ton carbon in the extracted timber were also relatively low (1.55 Mg m(-3) and 4.04 Mg Mg-1, respectively). Only emissions per area scaled with logging intensity. Emissions were dominated by the felled tree itself (in extracted logs and residuals), whereas hauling infrastructure (roads and log landings) contributed comparatively little. Unintended emissions could be reduced by 46% if concessions were able to achieve the best demonstrated outcomes in each source category and by 54% with additional improvements. Less than 5% of timber was lost due to hollow sections. We determined that it would be overly cautious to avoid cutting all trees with any hollow sections, and it would actually increase emissions per unit timber extracted if no other trees were cut in place of the hollow trees. At the tree level, certified concessions had higher log recovery and damaged fewer commercial species during felling, which should increase their current and future timber yields. It is important to both understand and improve carbon dynamics in managed forests in this emerging hotspot for greenhouse gas emissions from deforestation and forest degradation.