Parameterization of the CO2 and H2O gas exchange of several temperate deciduous broad-leaved trees at the leaf scale considering seasonal changes

A combined model to simulate CO2 and H2O gas exchange at the leaf scale was parameterized using data obtained from in situ leaf-scale observations of diurnal and seasonal changes in the CO2 and H2O gas exchange of four temperate deciduous broad-leaved trees using a porometric method. The model consists of a Ball et al . type stomatal conductance submodel [Ball, Woodrow & Berry, pp. 221-224 in Progress in Photosynthesis Research (ed. I. Biggins), Martinus-Nijhoff Publishers, Dordrecht, The Netherlands, 1987] and a Farquhar et al . type biochemical submodel of photosynthesis (Farquhar, von Caemmerer & Berry, Planta 149, 78-90, 1980). In these submodels, several parameters were optimized for each tree species as representative of the quantitative characteristics related to gas exchange. The results show that the seasonal physiological changes of V-cmax25 in the biochemical model of photosynthesis should be used to estimate the long-term CO2 gas exchange. For R-d25 in the biochemical model of photosynthesis and m in the Ball et al . type stomatal conductance model, the difference should be counted during the leaf expansion period.