"Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. Most of the population lives in the eastern part of the province. In the west, the relative height from mountain peaks to river valleys can be as much as 3,000 m. Yunnan is rich in natural resources and has the largest diversity of plant life in China. Of the approximately 30,000 species of higher plants in China, Yunnan has over 17,000. Yunnan's reserves of aluminium, lead, zinc and tin are the largest in China, and there are also major reserves of copper and nickel. Yunnan has over 600 rivers and lakes, which provide an annual water supply of 222 billion cubic meters. Projected hydropower reserves stand at 103 million KW, with an exploitable capacity of 90 million KW, capable of generating 349 KW of electricity annually."

Source: http://en.wikipedia.org/wiki/Yunnan