The Rainfall Interception Performance of Urban Tree Canopy in Beijing, China

Abstract

Green spaces play an important role in low impact development and runoff mitigation, but rain loss intercepted by tree canopies affiliated to green spaces are always overlooked. In this research, common garden trees in urban area were selected to explore the rainfall interception performance and the relationship between tree feathers and rainfall characteristics by monitoring variabilities including precipitation, interception, tree features, etc. for 24 rainfall events. The results show that ranging from less than 40.8 mm rainfall, interception increases and hasn’t saturated among most species, while rainfall rate declines. Interception of conifers declines when rainfall intensity increases but it not obvious in the deciduous. Interceptions show a positive correlation with crown density which means lusher trees may intercept more rain, but the interception effect would be damaged by garden pruning. Some species of deciduous trees such as lilytree, purple-leaf plum and maple have a better interception performance than conifers. Smaller branch angles may facilitate intercepting. Good performed species and appropriate managements are suggested to apply to LID to mitigate runoff.