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Abstract Drought stress has significant impacts on the structure and carbon cycling processes of forest ecosystems. Forest height (H), as a key vegetation structural parameter, plays a crucial yet poorly understood role linking vegetation responses to drought stress. This study, utilizing multi-source remote sensing datasets and forest dynamic monitoring across China, combined with the Standardized Precipitation Evapotranspiration Index (SPEI), systematically investigated the structure–function relationships and drought responses in forest ecosystems. Spatial analysis revealed that averaged forest height exceeded 39 m in southeastern China, while the leaf area index (LAI) displayed a decreasing gradient from southeast to northwest. Gross primary productivity (GPP) exhibited spatial coupling with structural metrics, as quantified by the fitted equation (GPP = − 1.54H + 12.94LAI + 92.8, R 2 = 0.71), confirming the synergistic regulation of photosynthetic efficiency by forest structure. A multi-temporal analysis of SPEI (1-, 3-, 6-, 12-month scales) identified cumulative drought intensification in northern arid zones, with drought-affected areas (SPEI < 0) covering 48% at the 12-month scale. Specifically, we found that drought duration mediated GPP responses through phase-dependent mechanisms: short-term drought (1–3 months) caused persistent GPP suppression, medium-term drought (6 months) permitted partial recovery, while tall forests suffered exacerbated GPP declines under long-term prolonged drought (12 months). By quantifying the relationship between drought stress, LAI, and GPP, this study demonstrated that forest height modulates drought adaptation through coordinated adjustments in LAI and GPP. These satellite-derived findings provide a mechanistic basis for regionally differentiated ecological restoration strategies. Critically, our results reveal that forest height plays a dual role: it can buffer the impact of short-term drought but may exacerbate ecosystem vulnerability under prolonged arid conditions.
Chen et al. (Mon,) studied this question.