Abstract
Global climate change is intensifying forest degradation, making the soil seed bank density (SSBD) in planted and natural forests a crucial resource for ecosystem restoration. Focusing on soil seed bank density can help us assess the potential of vegetation regeneration and maintain ecosystem stability and function. However, the macro-scale distribution differences and controlling mechanisms of SSBD in these forests remain elusive. This study focuses on the SSBD in 537 natural and 383 planted forest sites across China, examining the specific impacts of climatic, soil, and forest stand factors. It also predicts the pathways through which these factors modulate SSBD variations in both forest types. Our findings reveal that SSBD is significantly higher in planted forests compared to natural ones (P < 0.001). SSBD shows a marked declining trend with increasing temperature and precipitation (P < 0.001). In contrast, increases in sunlight duration and evapotranspiration positively correlate with SSBD in both forest types. Natural forests exhibit higher sensitivity to soil nutrient changes than planted forests. Both forest types show similar SSBD trends with changes in forest stand factors. Soil pH independently contributes the most to the spatial variation of SSBD in natural forests, while soil nitrogen content is the most significant contributor for planted forests. Mean Annual Temperature (MAT) and Mean Annual Precipitation (MAP) not only directly affect SSBD in natural forests but also indirectly through soil pH, forest stand density, and forest net primary productivity, with direct impacts outweighing the indirect. In planted forests, SSBD is primarily influenced directly by Mean Annual Evapotranspiration (MAE), MAP, soil nitrogen content, and stand density. Additionally, MAE and soil nitrogen content indirectly affect SSBD through forest stand density. Our results reveal that in forest management and administration, attention should not only be given to changes in climatic factors but also to soil nutrient loss.