Fig. 4 Structural Equation Model-fit path summary relating AGB to species richness via functional evenness and structural diversity metrics (Significant paths (P < 0.05) are represented with solid arrows and non-significant paths (P > 0.05) by dashed arrows. The single-pointed arrows represent causal paths and double-pointed arrows the residual correlations. The values without parentheses are the standardized path coefficients. The values with parentheses are the coefficients of determination. CV DBH: tree diameter variation; CV Nbp: variation of number of primary branches. Detailed statistics are shown in Tables 2-3.