Parameterization of Zelkova serrata stomatal conductance model to estimate stomatal ozone uptake in Japan

To parameterize stomatal conductance or ozone uptake modeling in the Eastern Asian tree species Zelkova serrata, measurements of stomatal conductance were carried out in several Japanese sites across the growing season. The new parameterization improved the stomatal conductance model performance relative to a previously proposed model. The results were used to compare the spatial distribution of AOT40 and Z. serrata stomatal ozone uptake in Japan. Including a soil moisture function improved the model in the short periods with low precipitation. In addition, elevated vapor pressure deficit and soil moisture deficit due to high temperature, and high ozone exposure induced stomatal closure. The consequent decoupling of stomatal ozone uptake from high ozone exposure suggests caution in using AOT40 as a standard for Z. serrata protection in Japan. (C) 2012 Elsevier Ltd. All rights reserved.