Managed forests have a profound effect on water resources and it is essential that we understand water flux within them in order to predict their response to climate change. In 2005, transpiration was measured on a fifteen minute time step in a hardwood nursery plantation via sap flow and gas exchange on five different deciduous species (Acer rubrum, Acer buergeranum, Prunus x yedoensis, Prunus serrulata and Platanus x acerifolia). In this study, we accounted for species-specific differences in transpiration by carefully examining each species' physiological response parameters in relationship to detailed site data and, in addition, the sensitivity of model input parameters. Species-specific transpiration was estimated with the three-dimensional MAESTRA model and predictions were compared to sap flux measurements. We found that dark stomatal conductance was the most significant parameter followed by dark respiration and once parameterized, estimates of seasonal average transpiration were similar to measured sap flow for all five species. The absolute percent difference ranged from 5.66 – 23.85 with Prunus x yedoensis and Prunus serrulata bracketing the extremities respectively. Of the study species, Prunus serrulata had the highest average seasonal daily water use at 19.2 Kg/m2/day (+/- 1.1), while the lowest was Acer rubrum L. at 3.9 Kg/m2/day (+/- 0.5). Lastly, results suggest that this approach may be useful to better explain the limiting factors to transpiration for mixed species forests.
