Carbon storage in vegetation and soil in Chinese ecosystems estimated by carbon transfer rate method

Abstract

AbstractTerrestrial carbon storage is split predominantly between vegetation and soils. However, the spatial distribution of terrestrial carbon and its presence in each carbon pool remains unclear. This study explored the spatial distribution of terrestrial carbon in these two carbon pools across Chinese ecosystems, which differ in vegetation types. Carbon storage was estimated using the carbon transfer rate method, which uses net primary productivity (NPP) and the turnover rate to estimate vegetation and soil carbon pools under the assumption of steady state. The distribution of carbon storage per unit area (carbon density) was shown based on the latest vegetation map (2008). Compared with recent estimates of 89.27 Pg C, our results showed that a total of only 55.46 Pg C have been stored over recent decades. Of this total, 18.19 and 37.27 Pg C were stored, respectively, in vegetation and in soil carbon pools. Among the eleven vegetation types in this study, needleleaf forest had the largest carbon storage (13.57 Pg C). The eleven vegetation types were classified into four major vegetation classes (forest, scrub, grass, and cultivated), of which forests had the higher carbon storage (21.7 Pg C) and the highest carbon density. Our estimates of the spatial distribution of carbon were consistent with previous studies. Both terrestrial and soil carbon pools exhibited higher carbon density in northeast China and the southeastern part of the Tibetan Plateau. Vegetation exhibited a high carbon density in eastern China but low carbon density in western China. Furthermore, our results had a higher spatial resolution of carbon distribution (75,000 polygon patches of the latest vegetation map) than previous studies. These results contribute to understanding carbon accumulation in different ecosystems.