Spatiotemporal Dynamics of Forest and Grassland and Their Effects on Carbon Balance in the Guanzhong Plain Urban Agglomeration

Currently, research that quantitatively disentangles the relative importance of these effects in terms of carbon balance and clarifies its independent mechanisms, particularly in ecologically sensitive urban agglomerations, is lacking. To address this gap, this study took the Guanzhong Plain Urban Agglomeration as a case study and used remote sensing imagery as the primary data source with the XGBoost–SHAP framework as the main analytical approach to quantitatively assess the importance and mechanisms of forest and grassland cover on carbon balance. The results indicate that forest and grassland cover in the Guanzhong Plain Urban Agglomeration slightly increased from 2000 to 2020, with a spatial pattern characterized by “more in the west and south, less in the east and north”. Forest and grassland cover contributes approximately 9.36% to carbon emissions, while it plays a dominant role in carbon sequestration, with an estimated contribution of approximately 79.07%. At the carbon balance level, its contribution reaches 9.55%. Furthermore, the results reveal significant spatial heterogeneity in the influence of forest and grassland cover on the carbon balance. The results of this study can provide important scientific basis for achieving the dual-carbon goal and formulating policies for the sustainable development of forest and grassland ecosystems.