Effects of forest thinning on interception and surface runoff in Larix principis-rupprechtii plantation during the growing season

Forest thinning is an important management strategy for altering the hydrological function of forests by redistributing of incident rainfall, and improving the capacity to store water on forest floor and in the soil. A study to analyze the water conservation functions of the forest canopy and forest floor was conducted on a 36-year-old Larix principis-rupprechtii plantation with different thinning treatments in the Taiyue Mountain of Shanxi Province. The results showed that the cumulative values of throughfall (TF) gradually increased with thinning intensity, whereas the cumulative values of stemflow (SF) and interception loss (I-c) decreased significantly. More importantly, the study revealed that combining I-c and interception loss of litter (I-l) yields a total interception flux of 21.9%, 24.5%, 23.8% and 19.7% of GR during the growing season in control, lightly thinned, moderately thinned, and heavily thinned respectively. Surface runoff as a proportion of GR varies tremendously depending on the amount and intensity of rainfall. Our findings demonstrated that rainfall redistribution through the forest canopy and litter and the potential for surface runoff responded to thinning intensity independently of each other. The intensity of management and plant-mediated biological processes are of particular importance in evaluating the impacts of forest management on hydrological processes in forests.