Potential vegetation modelling with variable leaf area index in semi-arid grassland of Loess plateau, China

The study was conducted in Zhulihe River Basin (between latitude 35°18´ and 36°34´ N and longitude 104°12´ and 105°33´ E), located in the west-central loess plateau. Here presented method for estimating the distribution of potential vegetation in the area studied. The method is based on the Penman-Monteith equation which includes the variable vegetation height and leaf area index (LAI). The heights of vegetation measured in a lot of quadrats over the region in 1996 were used to calculated vegetation LAI, aerodynamic resistance, vegetation canopy resistance and finally, the PET rate. The evaporation of rainfall intercepted by plants was calculated as one component of water use. According to the relationship between water need and apply, the distribution of potential vegetation can be confirmed. It is proposed that this type of method may be of use in the study of the dry layers (soil water content approximately to permanent wilting point) in a certain depth of soil profile and informal shape of trees (low productivity trees) grown on the loess plateau.