Quantitative association between the water yield impacts of forest cover changes and the biophysical effects of forest cover on temperatures

Abstract

Global studies have observed divergent impacts of forest cover changes on water yields and biophysical effects on local temperatures. These two topics have long been debated by the scientific community. Here, we built a quantitative link between the negative/positive effects of forest cover changes on water yields and the biophysical cooling/warming effects of forest cover on local temperatures. This model performs well across 12 paired watersheds and eddy covariance observations worldwide. Our results show that the directions of forest biophysical effects on temperatures are strongly related to the directions of water yield effects caused by the forest cover changes. In general, the water yield effects associated with forest biophysical processes increase significantly as climatic dryness increases; and these parts are usually larger than those from the background climate. Notably, the ratio of water yield differences to corresponding temperature changes caused by forest cover changes is larger in a dry climate than that in a humid climate. Our findings support the hypothesis that forest water yield in the dry climate regions is more sensitive to land cover changes than that in the humid climate regions. This study provides new insights into explaining the differences in water yield effects of forest cover changes between the dry and humid climates.