Predicting transpiration from forest stands in Belgium for the 21st century

Canopy transpiration is a major element of the hydrological cycle of temperate forests. Levels of water stress during the 21st century will be largely controlled by the response of canopy transpiration to changing environmental conditions. One year of transpiration measurement in two stands (Quercus robur L. and Fagus sylvatica L.) was used to calibrate the ASPECTS model on a1 and D0, two parameters of a modified version of Leuning’s equation of stomatal conductance. A second year of data was used to validate the model. The results indicate a higher sensitivity of gsc to vapour pressure deficit (Ds) in oak than in beech (D0 (oak)