Analysis of carbon storage response characteristics and driving mechanisms to land use change in mountainous and hilly regions

Scientifically revealing carbon storage response characteristics and underlying mechanisms to land use change is crucial for carbon neutrality and sustainable land use. This study employs a novel “macro-micro” analytical framework in Chongqing, a mountainous and hilly region in Southwest China. It first conducts a macro-scale assessment of response characteristics using bivariate spatial autocorrelation and a two-way fixed effects model. Then, a partial least squares structural equation model (PLS-SEM) deconstructs micro-level path mechanisms by which diverse driving factors influence carbon storage through land use. The results indicate that: (1) From 2000 to 2024, influenced by urban expansion and ecological protection, the study area's carbon storage increased by 164.95 × 10 6 t. Spatially, this exhibited heterogeneity: a decrease in the Main Urban Area, an increase in Northeastern Chongqing, and stability in Southeastern Chongqing. (2) A significant negative spatial correlation exists between land use intensity and carbon storage; a one-unit increase in intensity leads to a 41.617 t decrease in carbon storage, confirming high-intensity development's inhibitory effect. (3) Regional carbon storage results from comprehensive, superimposed effects of land uses and drivers. Path effects vary significantly: natural factors (topography, soil) shape the fundamental pattern by inhibiting cultivation and promoting woodland. Construction land expansion, driven by human activity and transport, impacts carbon storage, but its overall effect is relatively small. Woodland, driven by topography and soil, has a pronounced positive carbon storage gain effect. The study confirms that optimizing land use patterns and expanding woodland space are key pathways to achieve carbon neutrality in rapidly urbanizing mountainous regions.