Figure 2: Mean (±SE) leaf water potential at predawn (Ψpd), light-saturated net photosynthesis (Anet), and stomatal conductance (gs) for each sampling date in 2021 and 2022 for P. nigra , P. sylvestris , Q. faginea , and Q. ilex in monospecific (red), monofunctional (orange), multifunctional (light blue) and four-species mixture plots (dark blue). The stars indicate significant differences between mixed and monospecific plots at each sampling date (*0.05≥P>0.01; **0.01≥P>0.001; ***P≥0.001).