実測に基づく街路樹の植生蒸散モデルに関する研究

摘要

In this study, the details of the existing physiological models of plant transpiration, Jarvis and Kosugi models, were reviewed and field experiments were also conducted to investigate the influence of environmental factors on the transpiration of trees, particularly roadside trees. Data were collected by measuring the environmental factors and the factors influencing stomatal transpiration. The following results were obtained: (l) The transpiration of trees during the daytime was most significantly influenced by solar radiation or photosynthetically active radiation, followed by the leaf or air temperature. (2) The influence of the relative humidity of air on the total amount of transpiration of trees during the daytime was not significant.(3) On the prediction precision of the two models on plant transpiration, Jarvis and Kosugi models were almost the same.%近年、ヒートアイランド現象による都市熱環境の悪化に対して樹 木は日射遮蔽により地表面の温度上昇を抑制したり、蒸散に伴い日 射熱を地表面や他の固体物体よりもより多く潜熱に変換することに より周囲の空気温度上昇を抑制させる等の熱環境調節機能があるた め、都市熱環境改善効果が期待されている。しかし、一方で蒸散に よる周囲の湿度上昇や樹冠の抵抗による風速低下等によって、屋外 熱環境を悪化させる可能性もあるため、樹木の各熱環境調節機能を 総合的に評価することが必要となる。