Effects of the morphological characteristics of plants on rainfall interception and kinetic energy

Forests play an important role in the water cycle and in the control of soil erosion. The canopy, as the first active surface of the forest, directly affects soil erosion by redistributing rainfall. However, the effects of the plant morphological characteristics of different tree species on rainfall interception and kinetic energy reduction have not been determined. We determined 116 globally important woody tree species and classified them based on the differences of plant life-forms, leaf textures and trichomes on leaves in the Guizhou karstic regions of China. The water adsorbed on the branches and leaves of these species was measured to explain rainfall interception. We further selected four representative species among the 116 species and measured rainfall interception, stemflow and throughfall, as well as the corresponding indices of plant morphological characteristics, under simulated rainfall. Results indicated that the adsorbed water showed considerable differences between tree species with different plant morphological characteristics. Tree species with trichomes on their leaves had the largest amount of adsorbed water compared to those with papery or leathery leaves and those without trichomes. Rainfall interception was significantly dependent on leaf area index (LAI), mean leaf area (MLA) and leaf shape factor (LSF), but stemflow and throughfall were dependent on diffuse non-interceptance (DIFN) under tree canopies. Tree canopies increased the numbers, volumes and kinetic energy of large raindrops. LAI, mean foliage tilt angle (MTA), MLA and LSF had differently significant impacts on drop size distribution (DSD), and the kinetic energy of rainfall under canopies, but DIFN did not any impacts on them. The results presented in this study quantitatively clarify the impacts of the morphological characteristics of different plants on adsorbed water of branches and leaves, linking rainfall interception of canopies and the redistribution and kinetic energy of rainfall.