The Gongga Shan range, named after its highest peak Gongga Shan (30° N, 102° E, 7,556 m), is located in the transition zone between the Tibetan Plateau and the South Chinese plains. With a vertical difference of more than 6,300 m within a horizontal distance of only 11km, the eastward drop towards the Sichuan Basin is one of the largest in the world. At the same altitude the western slope is clearly warmer and drier than the eastern slope that is exposed to the summer monsoon. The upper limits of the various geoecological belts are up to 300 m higher on the western than on the eastern slope. This asymmetry cannot be explained by topoclimatological effects but by the mass-elevation effect of the Tibetan Plateau. It is regarded as a typical characteristic of the ranges bordering the Plateau. In contrast to other Chinese mountain ranges, the Gongga Shan range still has an extensive area of primary coniferous and deciduous forests up to an elevation of 4,000 m. The current policy of unrestricted logging, however, threatens to destroy these forests within 10-15 years.