Aboveground biomass is driven by mass-ratio effects and stand structural attributes in a temperate deciduous forest

1.Forest ecosystems are critical for the global regulation of carbon (C), a substantial portion of which is stored in aboveground biomass (AGB). While it is well understood that taxonomic and functional composition, stand structure, and environmental gradients influence spatial variation in AGB, the relative strengths of these drivers at landscape-scales has not been investigated in temperate forests. Furthermore, when biodiversity enhances C storage, it is unclear whether it is through mass-ratio effects (i.e., the dominant trait in communities regulates AGB) or through niche complementarity (i.e., increased AGB due to interspecific resource partitioning).

2.To address these mechanisms, we analyzed data from a census of 28,262 adult trees sampled across 900 ha of temperate deciduous forest in southwestern Pennsylvania. We used data on four key plant functional traits to determine if (1) there is a positive relationship between species diversity and AGB and (2) whether this is due to...