Widespread Declining Sensitivity of Chinese Forests to Soil Moisture Under Climate Change (2001–2020)

In the context of global climate change, quantifying the coupling relationship between forest growth status and soil moisture (SM) remains crucial for predicting ecosystem functional changes. However, systematic analysis of their dynamic coupling mechanisms is currently lacking. To address this gap, we systematically quantified the sensitivity of forest growth status to soil moisture and revealed its spatiotemporal patterns and driving mechanisms based on NDVI, LAI, and GPP data during the growing season of Chinese forests from 2001 to 2020. Results demonstrate that Chinese forests are experiencing a significant “soil moisture desensitization” process (|r| trend < 0, p < 0.05). Although forest growth status increased significantly (p < 0.05), sensitivity to soil moisture declined across 71% of forest areas, with only 26% showing increasing trends. Moreover, the area of soil moisture deficit regions (r > 0, p < 0.05) contracted sharply from 27% to 5%, while surplus regions (r < 0, p < 0.05) expanded by 7%. Attribution analysis reveals that solar radiation (~35%), precipitation (~25%), and atmospheric CO₂ concentration (~17%) represent the dominant factors driving sensitivity trends. This study provides new insights into hydrological response mechanisms of Chinese forests and holds important implications for optimizing ecological management and climate adaptation strategies.