Figure 4

Structural equation models linking aboveground biomass and species richness across forest strata, including the short tree (a), shrub (b), herb(c) and liana (d) layers. STR, SR, HR and LR represent the species richness of the short tree, shrub, herb and liana layers, respectively. STB, SB, HB and LB represent the aboveground biomass of the short tree, shrub, herb and liana layers, respectively. The other abbreviations are explained in Fig. 3.