Stand structural diversity and edaphic properties regulate aboveground biomass of Abies fargesii var. faxoniana primary forest on the eastern Qinghai-Tibetan Plateau.

Plant aboveground biomass reflects the resilience of ecosystem productivity to different environmental factors and plays an important role in biodiversity and ecosystem carbon cycles. Although many studies have investigated the relationship between aboveground biomass and species diversity, stand structural diversity is an important factor affecting ecosystem function. The mechanism of how climate and soil factors affect aboveground biomass through species diversity and structural diversity remains unclear. Here, combing data from 8 locations of Abies fargesii var. faxoniana primary forest, a structural equation model was used to study the effects of climate factors, soil factors, species diversity, and structural diversity on aboveground biomass. Our results demonstrated that climate factors affect aboveground biomass mainly through the indirect effect of species diversity. Species diversity indirectly affects aboveground biomass through its effects on structural diversity. Both direct effects of soil factors and indirect effects through structural diversity can significantly affect aboveground biomass. Therefore, maintaining higher diversity of stand structure and soil nutrients can improve aboveground biomass, and thus better improve ecosystem functions such as carbon storage. [ABSTRACT FROM AUTHOR]