Measuring and modeling species specific transpiration in a mixed hardwood plantation.

摘要

Differences in transpiration have been reported in tree species over the last several decades; however, few studies have teased out the environmental component with a common garden. Species specific transpiration was measured via sap flow on twenty trees from five deciduous hardwood species, Prunus x yedoensis Matsum., Acer rubrum L. 'Autumn Flame', Acer buergeranum Miq., Prunus serrulata Lindl. 'Kwanzan,' and Platanus x acerifolia (Ait.) Willd., throughout the 2005 growing season in a plantation. In addition, monthly growth and gas exchange measurements were collected for each species and used to parameterize a three dimensional spatially explicit transpiration model, MAESTRA. The model estimates predicted differences in species mean daily and hourly diurnal transpiration and we validated the model predictions against measured sap flow. Throughout the growing season, Prunus x yedoensis had the highest mean daily diurnal transpiration, 1.54 kg m-2 d -1, while Prunus serrulata had the single highest diurnal daily rate, 2.72 kg m-2 d-1. A sensitivity analysis was conducted to determine the effect that individual parameters have on predicting differences in transpiration and to focus model parameterization efforts. The dark stomatal conductance parameter was the most physiologically significant and was more than eight times more sensitive than the next closest importance parameter.