图3. 阔叶红松林树冠结构复杂性、均匀度指数、林分胸高断面积、环境因素(土壤全磷(P)和坡度结合的潜变量)与生产力之间的结构方程模型。A, 考虑树冠结构复杂性的模型。B, 考虑树冠垂直分层的模型。C, 考虑树冠可塑性的模型。图中实线表示作用路径显著, 虚线表示作用路径不显著。箭头旁边的值是每个路径的标准化回归系数和显著性。R²表示由组合自变量解释的因变量的总变化。*, p < 0.05; **, p < 0.01; ***, p < 0.001。

Fig. 3. Structural equation models (SEMs) for linking multivariate relationships among canopy structural complexity, evenness index, stand basal area, environmental factor (a latent variable of soil total phosphorus (P) and slope), and productivity in typical mixed broadleaved-Korean pine forest. A, Considering canopy structural complexity. B, Considering canopy vertical stratification. C, Considering canopy plasticity in the structural equation model. Solid lines indicate significant paths, and dash lines indicate insignificant paths. Standardized regression coefficients and significance are shown next to the arrow for each path. R² indicates the total variation in a dependent variable explained by the combined independent variables. *, p < 0.05; **, p < 0.01; ***, p < 0.001.