Objective This study aims to reveal the regulatory mechanisms of species diversity and structural diversity on tree growth in the broadleaved Korean pine forest of Changbai Mountain of northeastern China and to explore the effects of species diversity and structural diversity on community structure and growth.

Method Based on the field survey data of broadleaved Korean pine forest in Changbai Mountain in 2023, the forest was divided into different canopy layers. Correlation analysis and path analysis were used to study the relationship between community species diversity, structural diversity, and community growth indicators, including aboveground biomass, leaf area, basal area at breast height, and stand density.

Result (1) The diameter structure of species in the sample plots mainly presented three patterns: inverse-J shape, unimodal shape, and bimodal shape. (2) The understory layer exhibited the highest species diversity (Shannon index = 1.30) and species evenness (Evenness index = 0.90). Correlation analysis showed that species diversity was significantly positively correlated with aboveground biomass, leaf area, and basal area at breast height (P < 0.01), with the most pronounced effect observed in the midstory layer. (3) Path analysis indicated that species diversity significantly promoted community growth through direct effects, whereas the influence of structural diversity on growth indicators varied significantly among different canopy layers.

Conclusion Species diversity and structural diversity in different canopy layers of the broadleaved Korean pine forest in Changbai Mountain significantly affect community growth and ecological functions. Higher species diversity and an appropriate level of structural diversity contribute to the enhancement of aboveground biomass, leaf area, and basal area at breast height, improving forest productivity and ecological stability. The findings provide a scientific basis for stratified forest management and the ecological conservation of broadleaved Korean pine forests, helping to enhance the stability and sustainability of forest ecosystems.