Clear-cutting has been a widespread commercial logging practice, causing substantial changes of biodiversity in many forests throughout the world. Forest recovery is a complex ecological process, and examining the recovery process after clear-cutting is important for forest conservation and management. In the present study, we established fourteen 20 m × 20 m plots in three recovery stages (20-year-old second growth, 35-year-old second growth and old growth) and explored the changes in evergreen and deciduous species diversity after clear-cutting in a subtropical evergreen-deciduous broadleaved mixed forest in central China. The results showed that total species richness was highest at the intermediate recovery stage. The species richness and stem abundance of evergreen species increased, while total and deciduous species stem abundance decreased with forest recovery.The basal area of both total and evergreen species increased, while that of the deciduous species showed a unimodal pattern. The abiotic conditions varied with the recovery process. Changes in species compositions were generally correlated with soil pH, total phosphorus, and CO. Our results suggest that deciduous species richness and stem abundance can recover after 20-35 years, but evergreen species need more time to recover following clear-cutting.

Leaf habits (e.g., evergreen or deciduous) can reflect strategies of species adapting to varied environmental conditions. However, how species with different leaf habits coexist within a plant community is still poorly understood. Trait gradient analysis is a new approach to partition plant functional trait variations into alpha (within-community) and beta (among-community) components to quantify the effects of environmental filtering and biotic competition on community assembly. Here, on the basis of establishing forty-eight forest dynamic plots in a subtropical evergreen and deciduous broadleaved mixed forest in central China and measuring of seven functional traits, we compared the trait variation patterns and influencing factors of evergreen and deciduous species by using the trait gradient analysis method. The results showed that there were significant differences between functional traits for evergreen and deciduous species. Alpha trait components consistently varied more widely than beta components. The correlation between species trait mean and the alpha of each trait was highly significant, but there was no significant correlation between beta and alpha trait values. There were relatively weak or nonexistent significant correlations among species mean trait values and alpha trait values of different functional traits. However, the beta trait value showed high and significant correlations in both evergreen and deciduous species. Our results indicated that evergreen and deciduous species adopt similar adaptation strategies (beta component) in the context of environmental change in the community. However, the species initially came to coexist via the ecological positioning of traits (alpha component), which helped reduce competition so individuals could obtain more resources.

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