The Sichuan Basin
This is one of the most attractive geographical regions of China. The Sichuan Basin is surrounded by mountains, which are higher in the west and north. Protected against the penetration of cold northern winds, the basin is much warmer in the winter than are the more southerly plains of southeast China. Except for the Chengdu Plain, the region is hilly. The relief of the basin’s eastern half consists of numerous folds, forming a series of ridges and valleys that trend northeast to southwest. The lack of arable land has obliged farmers to cultivate the slopes of the hills, on which they have built terraces that frequently cover the slopes from top to bottom. The terracing has slowed down the process of erosion and has made it possible to cultivate additional areas by using the steeper slopes—some of which have grades up to 45° or more.