Study on Water Content Ratio of Tree Leaves from Point of View of Fire Prevention Effect

Abstract

There were some differences in the results of existing measurements on water content ratio of leaves. Therefore, the ratios of water content in 55 species of leaves were measured under the same conditions when leaf samples were taken. The result of measurement showed that there are differences in the water content between species and leaves. Next, seasonal changes in water content of leaves from 29 evergreen species were compared during summer and winter. As the result this comparison, it was found that the water content of leaves in Tokyo area is highest in summer. In addition to this, results of measurements assessing annual changes in water content of leaves from 6 broadleaf tree species indicated that the water content ratio in evergreen broad-leaved trees was at a minimum before coming into leaf during the winter and spring seasons. After showing the highest ratio of the season just after leaf flush, the ratio began gradually decreasing until the winter season. For deciduous broad-leaved trees, their ratio of water content has a tendency to be highest in April and drops temporarily in midsummer. Moreover, the results in this research and the results of existing measurements were integrated, the water content ratios of 178 species of trees were arranged and the tendency was grasped.