Modeling daily gas exchange of a Douglas-fir forest: comparison of three stomatal conductance models with and without a soil water stress function

• Published in: Tree physiology Vol. 20; no. 2; pp. 115 - 122
• Main Authors: Wijk, M.T. van, Dekker, S.C, Bouten, W, Bosveld, F.C, Kohsiek, W, Kramer, K, Mohren, G.M.J
• Format: Journal Article
• Language: English
• Published: Canada 2000
• Subjects: AIR TEMPERATURE; ALTERRA Wageningen UR; Bosecologie en Bosbeheer; CONTENIDO DE AGUA EN EL SUELO; DROUGHT STRESS; ECHANGE GAZEUX; ESTRES DE SEQUIA; Forest Ecology and Forest Management; GAS EXCHANGE; HUMEDAD RELATIVA; HUMIDITE RELATIVE; INTERCAMBIO DE GASES; Leerstoelgroep Bosecologie en bosbeheer; MODELE DE SIMULATION; MODELOS DE SIMULACION; NETHERLANDS; Netherlands, Garderen; PAISES BAJOS; PAYS BAS; PE&RC; PLANT WATER RELATIONS; PSEUDOTSUGA MENZIESII; RELACIONES PLANTA AGUA; RELATION PLANTE EAU; RELATIVE HUMIDITY; SAP FLOW; SIMULATION MODELS; SOIL WATER CONTENT; STOMATAL RESISTANCE; STRESS DU A LA SECHERESSE; TEMPERATURA DEL AIRE; TEMPERATURE DE L'AIR; TENEUR EN EAU DU SOL; TRANSPIRACION; TRANSPIRATION; USO DEL AGUA; UTILISATION DE L'EAU; Wageningen Environmental Research; WATER USE
• ISSN: 0829-318X; 1758-4469
• DOI: 10.1093/treephys/20.2.115

Modeling stomatal conductance is a key element in predicting tree growth and water use at the stand scale. We compared three commonly used models of stomatal conductance, the Jarvis-Loustau, Ball-Berry and Leuning models, for their suitability for incorporating soil water stress into their formulation, and for their performance in modeling forest ecosystem fluxes. We optimized the parameters of each of the three models with sap flow and soil water content data. The optimized Ball-Berry model showed clear relationships with air temperature and soil water content, whereas the optimized Leuning and Jarvis-Loustau models only showed a relationship with soil water content. We conclude that use of relative humidity instead of vapor pressure deficit, as in the Ball-Berry model, is not suitable for modeling daily gas exchange in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Speulderbos forest near the village of Garderen, The Netherlands. Based on the calculated responses to soil water content, we linked a model of forest growth, FORGRO, with a model of soil water, SWIF, to obtain a forest water-balance model that satisfactorily simulated carbon and water (transpiration) fluxes and soil water contents in the Douglas-fir forest for 1995.