Abstract: Plant functional traits affect plant growth and resource utilization strategies. Clarifying the changes in plant functional traits and their relationship with carbon storage during community succession under forest management is crucial for the accurate enhancement of forest quality and carbon sequestration. We analyzed the variation in community-level leaf and fine root functional traits of Cunninghamia lanceolata forests with different sprouting densities (high, moderate and low) at the early stage of succession in Baishanzu National Park. The relationship between these functional traits and above and belowground carbon density was evaluated. The results showed that: (1) With reduced C. lanceolata sprout density, the community-level leaf carbon content and leaf C/N ratio decreased, indicating a shift in the aboveground resource use strategy from conservative to acquisitive strategy. (2) The community-level root length density, root carbon and nitrogen contents decreased with decreasing sprout density, but the root C/N ratio increased, suggesting a shift in the belowground strategy from acquisitive to conservative. Moreover, the correlation between leaf and root traits was weak. (3) The aboveground, belowground, and total carbon density were significantly affected by leaf traits (explaining 48.9%, 84.6% and 72.0% of the variances, respectively). These findings are of great significance for regulating stand structure, optimizing tree species composition, and improving carbon sink function during plantation succession.

Key words: plant functional trait, carbon density, Cunninghamia lanceolata, tree species composition