The Yangtze is the longest river in China, and the third in the world. It originates from the north of the Danggula Mountains in Qinghai Province, dissects China's interior and then flows into the Pacific Ocean at Shanghai; it is 6,300 km long. The area of the Yangtze valley is 1,800,000 square kilometres, accounting for about 18.8 per cent of the land area in China. Some 34 per cent of the population of China live in the Yangtze valley. The output value of agriculture and industry accounts for 32 per cent and 28 per cent respectively of that of China, which makes the Yangtze valley one of the most developed belts in the country. However, due to the deterioration of the ecological and environmental functions of the valley, natural disasters such as floods have become more frequent in the last 50 years. This threatens the ecological safety of the Yangtze valley.
The upper reaches of the Yangtze river are sensitive to environmental change, and disturbances here can result in disasters along the valley. For this reason it is the attempts to restore the ecological health of the upper reaches of the valley that this chapter discusses. The upper reaches begin at Yichang, Hubei Province (see Figure 14.1). They cover 1,054,000 square kilometres, some 58.9 per cent of the Yangtze valley. The population is 163 million, accounting for 40 per cent of that of the valley. The largest settlements are provincial administrative units at Qinghai, Xizang, Sichuan, Ganshu, Shanxi, Yunnan, Guizhou, Chongqing and Hubei. Ethnic minorities such as the Tibetan, Qiang and Yis are the majority population (Yang Dingguo 1996).
This zone is biologically diverse, supporting more than 4,100 species of medicinal plants. The giant panda, red panda and snub-nosed monkey are some of its most famous rare animals. The ecological and cultural importance of the region is reflected in its many reserve areas. The Hengduan (Transverse) Mountain Region has been defined one of the 25 protected hot spots of biological diversity by Conservation International. The Ermei Mountain-Leshan figure of Buddha, Jiuzhaigou (a beauty spot), Huanglong Temple (an outstandingly beautiful calcified landscape), Du Jiang weirs (given