Objective Pinus koraiensis and Tilia amurensis, the dominant species in the coniferous and broad-leaved mixed forest in Jiaohe, Jilin Province, were taken as the research object. We investigated the interspecific differences in leaf traits, correlations among leaf traits, and the effects of biotic factors (neighborhood competition, initial DBH, leaf traits) and abiotic factors (topographical factor) on the growth rate of trees.
Method Welch ANOVA was used to quantify the interspecific differences in leaf traits of Pinus koraiensis and Tilia amurensis. Principal component analysis (PCA) and spearman correlation coefficient were used to evaluate the correlation between leaf traits. The relative effects of different factors on the growth rate of Pinus koraiensis and Tilia amurensis were calculated by ordinary least squares model (OLS).
Result The results showed that the light-saturated photosynthetic rate and leaf dark respiration of Pinus koraiensis were significantly higher than those of Tilia amurensis; light-saturated stomatal conductance and specific leaf area of Tilia amurensis were significantly higher than those of Pinus koraiensis. The light-saturated photosynthetic rate of Pinus koraiensis was positively correlated with light-saturated stomatal conductance and specific leaf area. The light-saturated photosynthetic rate of Tilia amurensis was positively correlated with light-saturated stomatal conductance and negatively correlated with specific leaf area. Initial DBH (P < 0.05), neighborhood crowding index (P < 0.01) and slope (P < 0.05) had significant negative effects on average annual DBH growth of Pinus koraiensis. Initial DBH (P < 0.001) had significant positive effect on average annual biomass growth of Pinus koraiensis, neighborhood crowding index (P < 0.05) and slope (P < 0.05) had significant negative effect. Initial DBH had significant negative effect on average annual DBH growth (P < 0.001) and positive effect on average annual biomass growth (P < 0.05) of Tilia amurensis. Altitude had significant negative effects on the average annual DBH growth (P < 0.01) and annual biomass growth (P < 0.01) of Tilia amurensis.
Conclusion The leaf traits of Pinus koraiensis and Tilia amurensis had significant interspecific differences, the correlation of leaf traits of the two species had different patterns. The growth of Tilia amurensis was affected by the initial DBH and elevation. The larger the initial DBH, the lower the average annual DBH growth, and the higher the average annual biomass growth. The higher the elevation, the lower the average annual DBH growth and biomass growth. The growth of Pinus koraiensis was affected by the initial DBH, neighborhood crowding index and slope. The larger the initial DBH, the lower the average annual DBH growth, while the higher the average annual biomass growth. The larger the neighborhood crowding index and slope, the lower the average annual DBH growth and average annual biomass growth.
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