Maximum potential of vegetation carbon sink in Chinese forests

Forest vegetation is essential in sequestering carbon dioxide (CO₂) from the atmosphere and mediating global warming. The carbon (C) sink potential of forest vegetation in different provinces is vital for policymakers to develop C-neutral technical routes and regional priorities in China; however, the mechanism remains unclear. In this study, we compiled the public data on forest vegetation biomass or storage along forest succession series between 2003 and 2022 and obtained the spatial variation of the maximum C storage(BC_max) of forest vegetation using classic logistic equation and nonlinear fitting. Furthermore, the C sink potential (∆C_pot) of the Chinese forest vegetation was calculated based on the differences between the BC_max and intensive field-investigated data in the 2010s. The results showed that the BC_max in the Chinese forest vegetation was approximately 19.03 Pg. The BC_max in southwest and northeast China were higher than those in other regions. The ∆C_pot was estimated as 8.83 Pg. Moreover, 1 km × 1 km spatial raster data for ∆C_pot were produced using the spatial raster calculation. Similarly, the per capita ∆C_pot of regions with low economic development (southwest, central, and southern Chinese provinces) were five to ten times higher than those of regions with a higher economic level. The ∆C_pot correlated negatively with gross domestic product (GDP)across all Chinese provinces. Our findings provide new insights into the ∆C_pot of the Chinese forest vegetation under natural restoration and emphasize that some differences in financial and political support among different provinces facilitate achieving a large ∆C_pot for C neutrality.