Objective To study the characteristics of forest species diversity across different succession stages under both natural and artificial restoration methods, for providing a scientific theoretical basis for the management, protection and restoration strategies of subtropical forests.

Method Based on five forest types in Jiulian Mountain in Jiangxi Province, including secondary forests of 20 and 40 years after natural restoration, Chinese fir forest of 20 and 40 years after artificial planting and old forest, eight 50 m × 50 m plots were established for each forest type. Using the method of space-for-time substitution, one-way ANOVA and Tukey multiple comparison were used to analyze the differences of species diversity and community structure of forest communities between natural and artificial restoration models and the old-growth forest.

Result The recovery effects on species composition, species diversity and community structure varied in different recovery models. Naturally restored secondary forests showed a short-term advantage in the recovery of species diversity (species composition similarity between 20-year-old secondary forests and old forests reached 32.6%, and species richness reached 74% of that in old-growth forest). However, community structure recovered more slowly-the basal area of 40-year-old secondary forests was 57.9% of that in old-growth forest. In contrast, Chinese fir plantations exhibited faster structural recovery with the basal area in 20-year-old Chinese fir forests reaches 72.3% of that in aged forests), but species diversity remained lower in the long term- species richness in 40-year-old Chinese fir forests was only 68.5% of that in old-growth forests. The coefficient of variation of breast diameter in old-growth forests was highest in old-growth forest, reflecting greater individual differentiation due to natural competition, whereas planted forests showed higher uniformity.

Conclusion By comparing the dynamic differences between the natural restoration and artificial restoration models, this study reveals a phased trade-off mechanisms between the two paths in terms of ecological restoration efficiency and function. Natural restoration facilitates faster recovery of species diversity and composition in the short term, while artificial restoration supports more rapid structural recovery. These findings challenge the traditional static view that natural restoration is universally superior to artificial restoration, providing an innovative theoretical basis and practical pathway for stage-specific design of subtropical forest restoration strategies.