The three-dimension zonal pattern of soil organic carbon density in China’s forests

Abstract

The three-dimensional zonality of soil organic carbon (SOC) density (C storage per unit area) is a scientific basis for estimating the potential of regional forest carbon sequestration on a large scale. To understand the three-dimensional zonality of forest SOC density in China and the effect of plantations on these zonal patterns, data on China’s forest SOC density were collected from 231 published studies. The average forest SOC density was 122.72 Mg ha−1, and SOC density in natural forests was significantly higher than that in plantations in China. In addition, forest SOC density significantly increased with increasing latitude (r2 = 0.04, P < 0.001) and elevation (r2 = 0.108, P < 0.001) and showed a quadratic relationship with longitude (r2 = 0.204, P < 0.001). However, the three-dimensional zonality of SOC density in natural forests was significantly higher than that in plantations. Specifically, plantations weakened the linkages between forest SOC density and geographical factors. The results imply that increasing plantations may weaken the three-dimensional zonality of China’s forest SOC density. Thus, these results are particularly important for improving carbon cycle models and evaluating the carbon sequestration potential of China’s forest.