资源环境科技发展态势分析平台

Forests are a major contributor of terrestrial ecosystem carbon pools. Accurate estimates of forest biomass carbon sinks can improve our understanding of carbon cycles and help in developing sustainable forest management policies in the face of climate change. In this study, we update estimates of the biomass carbon stocks of China's forests based on seven forest inventory datasets from 1977 to 2013 and carbon fraction coefficients of 46 tree species in the continuous biomass expansion factor (CBEF) model. Our findings suggest that (1) China's forest stands acted as an average biomass carbon sink of 99.07 Tg C year(-1); and (2) biomass carbon stocks increased by 72.62% from 1977 to 2013 and recently reached 7.27 Pg C, driven by forest area expansion and forest growth. The biomass carbon density of forest stands (canopy coverage > 20%) increased from 38.18 to 44.52 Mg C ha(-1) during the study period, with higher carbon densities in natural compared to planted forests, and the gap increasing with forest age. The largest increases in the biomass of carbon stocks of forest stands occurred in the eastern and northern regions. Our results suggest that biomass carbon stocks of natural forests account for about 85% in the most recent inventory and that the total biomass carbon stocks of forest stands in China will keep increasing in the future because of the large area of planted forests with young and middle-aged forest growth. The results from this study can help with comprehensive investigations of forest carbon budgets and the calibration and validation of simulation model results.