NAME =  Takashi KUWADA  
ORGANIZATION =  Japan Science and Technology Agency  
ADDRESS =  Laboratory of Forest Meteolorogy and Hydrology, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601  
COUNTRY =  Japan  
PHONE =  +81-52-789-5038  
FAX =  +81-52-789-5038  
E-MAIL =  takashi7@agr.nagoya-u.ac.jp  
POSTER_ONLY =  yes  
THEME =  T5  
DATE =  30-Jul-04-13:56:57  
ABSID = T5TK30Jul04135657 
TITLE = Physiological responses of eastern Siberian boreal larch and pine to the environmental factors at the leaf and canopy scale 
AUTHOR_1 = Takashi KUWADA 
INSTITUTION_1 = Japan Science and Technology Agency 
PRESENTER = AUTHOR_1 
AUTHOR_2 = Takeshi OHTA 
INSTITUTION_2 = Graduate School of Bioagricultural Sciences, Nagoya University 
AUTHOR_3 = Ken YOSHIKAWA 
INSTITUTION_3 = Faculty of Agriculture, Okayama University 
ABSTRACT = Stomata play an important role that links regional and global climate with water, carbon and nutrient cycles by controlling the water movement from the soil through the plants to the atmosphere.  In order to predict the effect of the global climate change, it is necessary to improve our understanding of stomatal response to the environmental changes and the subsequent changes in evapotranspiration from the various ecosystems.  However, there is little information about the relationships between the leaf-level stomatal response and canopy-level stomatal response to the environmental factors, which forms the basis for up-scaling physiological process in time and space.  We analyzed the data obtained at eastern Siberian boreal larch and pine forest using big-leaf model including the Jarvis type conductance model.  These forests have relatively low leaf area index and more direct sunlight reaches their understory.  Therefore, there is a significant contribution of the understory vegetation to the forest evapotranspiration.  The parameters of the conductance model related with the short wave radiation, air temperature and vapor pressure deficit of the air (VPD) were fitted.  In both of larch and pine, the maximum canopy stomatal conductance was 6 to 7 times greater than the maximum stomatal conductance.  The stomatal conductance reached saturated values at the lower short-wave radiation condition as compared to the canopy stomatal conductance.  Canopy stomatal conductance showed lower optimal temperature for evapotranspiration compared with the stomatal conductance.  In case of pine, canopy stomatal conductance decreased more sharply with VPD than the stomatal conductance.  It is suggested that different environmental controls of evapotranspiration existed in these two forests.