Effects of Tree Diversity, Functional Composition, and Large Trees on the Aboveground Biomass of an Old-Growth Subtropical Forest in Southern China

Forest aboveground biomass (AGB) plays an important role in regulating the global carbon cycle and is thus essential component of ecosystem functioning. In relationships between biodiversity functioning (BEF), studies have shown that many biotic factors (e.g., species, functional traits, large trees) abiotic significant impacts on AGB. However, relative strength these affecting remains unclear. this study, we analyzed woody plants (diameter at breast height [DBH] ≥ 1 cm) within a 1.6 ha plot old-growth subtropical natural forest southern China. We used structural equation models to test effects tree diversity (species, phylogenetic, functional, size inequality), composition, trees, environmental (topography, soil nutrients, understory light) Our results indicated inequality, community-weighted mean maximum DBH (CWM_MDBH), trees had significant, positive AGB (p < 0.001), while lower phosphorus content was found promote increase Furthermore, which were mostly composed dominant main driver AGB, effect composition CWM_MDBH) substantially reduced by trees. argue selection key BEF forests conclude retaining large-diameter along with sustaining complex stand structure, are measures for improving productivity.