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Hoshika, Yasutomo*; Watanabe, Makoto*; Katata, Genki; De Marco, A.*; Deushi, Makoto*; Carriero, G.*; Koike, Takayoshi*; Paoletti, E.*
no journal, ,
Ozone (O) enters leaves via stomata and causes a damage to leaves of trees. Modeling of stomatal conductance (g
) is considered as an essential factor to assess O
impacts. In this presentation, our recent progress of research for the modeling of g
under elevated O
is summarized. First, we investigated g
parameters of the Jarvis-type model for forest tree types throughout the world. The optimal temperature of g
and g
response to predawn water potential changed according to the growth conditions. Next, an optimization model of stomata including O
effects was tested in free-air O
exposure experiment on Siebold's beech in Japan. The optimal stomatal model explained O
-induced stomatal closure in early summer. However, in late summer and autumn, the model did not explain the effects of O
on g
. This reflects the loss of closing response of stomata by O
(stomatal sluggishness) such as under low light conditions. Finally, we examined the effects of O
-induced stomatal sluggishness on carbon gain and transpiration of temperate deciduous forests in the Northern Hemisphere by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. Our findings are consistent with previous experimental evidences, suggesting significant impairment of forest carbon and water balances attributed by O
-induced stomatal sluggishness.