Carbon storage of the cropland and forest systems in the eastern three provinces based on an improved InVest model

Based on existing literature, we compiled the baseline carbon pool data for the study area. Annual soil organic carbon (SOC) change coefficients were derived accordingly. For cropland systems, these coefficients were obtained from published studies based on specific cropland types. For forest systems, forest age structure was incorporated by classifying stands into different age cohorts and integrating refined forest type classifications. The SOC change coefficients were then synthesized from multiple relevant studies.Temporal updates of soil carbon density were conducted using land-use data from 2015 and 2020 to distinguish between unchanged and converted areas. Spatiotemporal changes in soil carbon density were quantified using a specified equation, which integrated baseline carbon density, annual change coefficients, and temporal factors.Finally, the updated dynamic soil carbon density data, along with other static carbon density data, were incorporated into the InVEST model to estimate the carbon storage in agricultural and forest ecosystems of the three northeastern provinces under the refined carbon density scenario.