Effects of land use and cover change (LUCC) on terrestrial carbon stocks in China between 2000 and 2018

The land-use and cover change (LUCC) is a major factor in the terrestrial carbon cycle. However, the changes of vegetation biomass and soil carbon sequestration caused by land-use conversion have large uncertainties. In the study, we determined the LUCC features through the method of performing transition matrix and transfer trajectory analysis during 2000–2018. By integrating the 3-PGS model and an empirical bookkeeping model, we also explored the carbon budget from land-use conversion in the terrestrial ecosystem of China. The results demonstrated significant losses in grassland (36.22 × 106 ha), farmland (1.39 × 106 ha), and large expansion of built-up land (9.46 × 106 ha), woodland (3.59 × 106 ha). The study revealed that LUCC was driven by natural factors (11.05%) and human activities (8.25%), and natural factors, such as climate, natural vegetation succession, and other natural disturbances, were slightly higher. The total carbon storage caused by LUCC has been increased by approximately 1.32 Pg C, which stored in vegetation biomass (1.11 Pg C) and soil (0.21 Pg C), respectively. Large carbon losses (approximately 29.81 Tg C/yr) have resulted from deforestation, whereas carbon gains happened with the Grain to Green activity, cultivation, and afforestation. Overall, LUCC has a significant effect on increasing sinks in the terrestrial carbon pool in China. Our findings have implications for improving the estimation accuracy of carbon pools and comprehending the impact of human activities on regional carbon balance in China's terrestrial ecosystem.