Climate factors affect forest biomass allocation by altering soil nutrient availability and leaf traits

Biomass in forests sequesters substantial amounts of carbon; although the contribution of aboveground biomass has been extensively studied, the contribution of belowground biomass remains understudied. Investigating the forest biomass allocation is crucial for understanding the impacts of global change on carbon allocation and cycling. Moreover, the question of how climate factors affect biomass allocation in natural and planted forests remains unresolved. Here, we addressed this question by collecting data from 384 planted forests and 541 natural forests in China. We evaluated the direct and indirect effects of climate factors on the belowground biomass proportion (BGBP). The average BGBP was 31.09% in natural forests and was significantly higher (38.75%) in planted forests. Furthermore, we observed a significant decrease in BGBP with increasing temperature and precipitation. Climate factors, particularly those affecting soil factors, such as pH, strongly affected the BGBP in natural and planted forests. Based on our results, we propose that future studies should consider the effects of forest type (natural or planted) and soil factors on BGBP.

Automated summary

The contribution of belowground biomass in forests, although less studied, plays a significant role in carbon sequestration. This study investigated the effects of climate factors on belowground biomass proportion (BGBP) in 384 planted forests and 541 natural forests in China. The results revealed that the average BGBP was higher in planted forests (38.75%) compared to natural forests (31.09%), and there was a significant decrease in BGBP with increasing temperature and precipitation. Climate factors, particularly those influencing soil factors, strongly influenced BGBP in both natural and planted forests.