In the Loess Plateau in Northwest China, desertification of agricultural lands by soil erosion is the most serious problem, and it is induced by overuse of hill slope for grazing and agriculture. It is needed to clarify the process of erosion in relation to the topography and to select tree species to be planted in semi-arid area. From our study, susceptibility of slopes to erosion is different between topographical types, and forest vegetation can protect lands from erosion where annual rainfall exceeds 450 mm. Among trees planted there, Pinus tabulaeformis was found to have higher water-use-efficiency (WUE) than poplars and Robinia pseudoacacia, and it increases water content of soil and facilitates development of ground vegetation.
Loess Plateau, topography, precipitation, water relations of trees