Abstract:It is necessary to study on the real transpiration of forests in growth seasons, to solve the problems of adjusting forest density, improving water use efficiency and maintaining forest stability of the shelter forest in semiarid area. The experimental site in this study locates at Runoff Forestry Experimental Station of Beijing Forestry University in Fangshan , Shanxi (north latitude 37°36′58″,east longitude 110°02′55″). It has an average altitude of 1,200 m, average precipitation of 416 mm and average p...