Forest stand factors determine the rainfall pattern of crown allocation of Picea schrenkiana in the northern slope of Mount Bogda, Tianshan Range, China

The middle elevation forest of the Tianshan Mountains, dominated by the conifer tree , is an important part of the mountain ecosystem of arid Northwestern China, which plays a pivotal role in carbon sequestration and water conservation. As the first interface of water transfer in a forest ecosystem, tree crown allocates precipitation regulating soil water supply and sustaining vegetation growth below the crown. In this study, four 20-m × 20-m sampling quadrats were randomly installed at each of three elevation sites (2,200 m, 1,800 m, and 1,450 m) on the northern slope of Mount Bogda, the main peak of the Eastern Tianshan Range. The effects of forest stand factors and incoming rainfall on forest crown allocation of precipitation were investigated, and the trade-off between water and carbon was also discussed. The results revealed that (1) the interception, throughfall, and stemflow ratio had values of 44.3%-50.0%, 49.6%-55.4%, and