Figure legends

Figure 1 | Conceptual diagram of how functional trait dispersion and identity influences the tree mixture effect on productivity, both across and within species richness levels. (A) Mixtures (representing by circles) consisting of different species are distributed along the gradient of species richness in mixtures (SR), functional dispersion (FD), and functional identity (from conservative to acquisitive). The blue area (a) demonstrates species mixtures with increasing FDis or acquisitive strategies across the SR levels. Alternatively, the green area (b) demonstrates species mixtures with low variation of FDis or acquisitive strategies across the SR levels. The red area demonstrates species mixtures with increasing FDis or acquisitive strategies at a constant SR level. (B) The different lines are our predictions according to the different situations in panel A. The blue line (a) assumes a positive relationship between lnRR and SR with increasing FDis or acquisitive strategies. The green dashed line (b) assumes a nonsignificant relationship between lnRR and SR, with a low variation of FDis or acquisitive strategies. The red line (c) assumes a positive relationship between lnRR with increasing FDis or acquisitive strategies at a constant SR level.
Figure 2 | Global distribution of the 59 studies included in the meta-analysis.
Figure 3 | Relationship between species richness with plant functional dispersion (a) and with the tree mixture effects on productivity (b). Dashed and solid blue lines are non-significant and significant mixed-effects models fit across all studies, respectively. Light blue bands represent 95% confidence intervals. The sizes of the circles represent the relative weights of corresponding observations. Curves with their 95% confidence interval (shaded) were estimated by partial regressions, with corresponding levels of significance (P ). All numerical variables were natural log-transformed.
Figure 4 | Relationship between the tree mixtures on productivity (lnRR) with multidimensional functional dispersion (a), and with single trait dispersion (b-d). Blue lines are mixed-effects models fit across species richness levels. Light blue bands represent 95% confidence intervals. Red, green, and yellow lines are mixed-effects models fit within two-, three-, and four-species mixtures, respectively. The sizes of the circles represent the relative weights of corresponding observations. Curves with their 95% confidence interval (shaded) were estimated by partial regressions with corresponding levels of significance (P ). All numerical variables were natural log-transformed.
Figure 5 | Relationship between the effects of tree mixtures on productivity with the CWM of species mixtures. (a) Leaf nitrogen content (LNC). (b) Specific leaf area (SLA). (c) Wood density (WD). Blue lines represent mixed-effects models fit across species richness levels. Light blue bands represent 95% confidence intervals. Red, green, and yellow lines are mixed-effects models fit within two- , three-, and four-species mixtures, respectively. The sizes of the circles represent the relative weights of corresponding observations. Curves with their 95% confidence interval (shaded) were estimated by partial regressions with corresponding levels of significance (P ). All numerical variables were natural log-transformed.

Figure 1