Fig. 5: Effect of P₅₀ parameter value on projections of future required maximum whole-plant hydraulic conductivity (K_w,max(req)).

Change in K_w,max(req) as vapor pressure deficit (VPD) increases according to future projections for Central America. The x-axis is a multiplier of increase from the present. For example, 2.00 means VPD is doubled from the current hourly values for each month. The lines represent K_w,max(req) under potential future VPD conditions spanning 1x to 2x current VPD at the dry forest site, Horizontes, Costa Rica (red) and the moist forest site, Barro Colorado Island, Panama (BCI, blue). A tree K_w,max(req), B liana K_w,max(req). Symbols at 2.00 on the x-axis of each panel represent K_w,max(req) under various conditions of P₅₀ adaptation when VPD is doubled from present. Triangle: tree P₅₀ = liana P₅₀ = −2.25 MPa; diamond: tree P₅₀ = liana P₅₀ = −2.5 MPa; square: tree P₅₀ = liana P₅₀ = −3.0 MPa.