The southern part of Hengduan Mountains is a region of the highest latitude and the highest altitude that the northward shifting rubber trees successfully grow in China.In winter, the rubber-growing regions of the Hengduan Mountains are under the control of Indian continental dry-warm air mass with prevailing west wind. The weather is clear and the temperature is higher, since the Ailao Mountain, Wuliang Mountain and Nu Mountain protects the tropical plants from damages of the north cold air.Another characteristic is the great range of the vertical variation in height and also in climate. Under 1000 metres above sea level, the minimum temperature of the wintry clear night rises with the height, and an inversion layer is formed. The rubber trees grow at 700-1000 metres above sea level, which is called thermal belts on slopes. Under 700 metres above sea level the rubber trees, will be harmed the cold air of the lakes in winter, above 1000 metres above sea level, the temperature decreases with height, the rubber trees can not grow up.700-1000 meters is the best altitude for the rubber trees to grow, not only because of the warm belt formed dy inversion, but also of the abundant precipitation formed by the slope.