Abstract: Ecosystem stability is a comprehensive characteristic of forest community structure and function. The mechanism of forest ecosystem stability was explored using 10-year field survey data from a 21.12 hm² natural coniferous and broad-leaved mixed forest plot in Jiaohe, Jilin Province (i.e., three-time repeated in 2009, 2014, and 2019). We analyzed the direct and indirect effects of species asynchrony, species diversity, stand density and elevation on temporal stability of aboveground biomass, and quantified their relative importance in driving temporal stability of aboveground biomass. The results showed that there was a significant positive correlation (P<0.001) between the biomass temporal stability and species asynchrony, stand density and elevation, with the path coefficients being 0.546, 0.249, and 0.151. There was a significant positive correlation between biomass temporal stability and species richness (P<0.05), and the path coefficient was 0.086. There was no significant correlation between biomass temporal stability and stand structure (P>0.05), with a path coefficient of 0.021. There was a significant positive correlation between elevation and stand density (P<0.001), with a path coefficient of 0.443, which had significant indirect effect on biomass stability. Compared with other stand factors, species asynchrony was crucial in regulating biomass temporal stability. Biodiversity enhanced ecosystem stability through species asynchrony. Based on the results of structural equation modeling, we analyzed the relative effects of biotic and abiotic factors on the temporal stability of biomass in natural mixed coniferous and broadleaf forests, which is of practical significance for understanding forest ecosystem stability and forest sustainable management.

Key words: temporal stability, biodiversity,  , species asynchrony, stand structure, forest ecosystem.