Impacts of the impervious surfaces on the water use by urban trees: Hydrogen isotope analysis

As the urban area is expanding and the populations of cities are growing, the role of urban trees in regulating biogeochemical cycles in urban regions is becoming more important. In particular, impervious surfaces in urban regions greatly disturb water use by trees. Here, we investigate the impacts of the anthropogenic structures on the water use pattern of trees on the Seoul National University campus. We select two types of gingko (Ginko biola L.) : one has been stabilized surrounded by impervious blocks and the other has been grown in natural conditions. To track the source of tree water use, xylem water at stem and soil water at 0-10, 40-50 90-100-cm depth are collected before and after precipitation for all trees. Precipitation is collected just after the rainfall event. Hydrogen isotope ratios of precipitation, soil water and xylem are analyzed to attribute source in tree water use. Finally we discuss the effects of impervious surfaces on root development and water use efficiencies.