Fig. 2: Key trait associations along the two dimensions for the forest communities.

a Biplot resulting from the principal component analysis (PCA) of eight functional traits at the community level. There were 12,452 forest communities used in our analysis. The community weighted-mean trait was calculated based on all species-level trait values weighted by the proportions of the species basal area within a community. The dominant forest type was identified according to the relative proportion of dominant types representing more than 50% of the community basal area: BD (broadleaved deciduous, blue, 5584 communities); BE (broadleaved evergreen, green, 407 communities) and NC (needleleaved conifer, red, 6461 communities). b The Pearson correlation coefficients between the functional traits at the community level (all p values < 0.001). The Pearson correlation tests are two-sided. Abbreviations of functional traits: N leaf nitrogen content, Ks maximum xylem conductivity per unit sapwood area, LS leaf area to sapwood area ratio, LMA leaf mass per area, P50 xylem water potential at 50% loss of conductivity, Slope for the embolism vulnerability curve between P50–P88, TLP leaf turgor loss point and WD wood density. Traits explanations are provided in Table 1. The elements in panel a are created in BioRender. Zhang, C. (2024) BioRender.com/u64o243.