Increasing the ratio of vegetation coverage has been regarded as one of the key measures in controlling soil erosion and land desertification in the arid and semi-arid western regions of China. Clearing forests and grasslands for farming and cultivated land on steep slopes to resolve the insufficiency of food and economic income has been rooted in Chinese farmers' minds and government policy for hundreds of years. This has resulted in a large environmental deterioration in most regions of western China. The...