Fig. 7.

Structural equation modeling (SEM) on key leaf functional traits at Huzhong (a, b) and Linzhi (c, d) sites. Direct (DE) and indirect effects (IE) are given at both Huzhong (b) and Linzhi (d) sites, respectively. Solid blue and red arrows represent significant positive or negative relationships at p < 0.05 levels, whereas dashed blue and red arrows represent no significance (p > 0.05). Values above arrows indicate the standard path coefficients, and their significances at 0.05, 0.01, and 0.001 levels are marked by *, **, and ***, respectively. Percentages on rectangles indicate the variance explained by the models. For abbreviations, see Fig. 1; and for SEM statistical information, see Table S7