关键词: 青藏高原东南部, 雪线, 林线, 空间分布, 气候条件

Abstract: The southeastern part of Qinghai-Xizang plateau is a typical region in which there are glaciers and dark coniferous forests. Some conclusions were obtained based on the study of altitudes of regional snowline, regional timber line, temperature, precipitation and their relationships: 1. Because of the decrease of precipitation from the margin to the inland of Tibet and of the temperature-rising effect of Tibet in summer, snowline and timber line rise from southeast margin of the plateau to the inland, which has interrupted the normal latitude distribution law. 2. Temperature, precipitation annual distribution of precipitation and the perantage of snow in annual precipitation are all the factors cotrolling the spatial distribution of snowline when the lo.west requirement for temperature and precipitation to form snowline were met. 3. When the lowest growth requirement for precipitation was met, the annual amplitude of temperature and its annual distribution controll spatial distribution of tember line. 4. The altitude difference between snowline and timberline, which depends on snowline controlled by precipitation, is different in different climate zones. 5. It is certain that all the glaciers in the region where there is no periglacial zone are the most typical temperate glacier, as seen in the southeast Xizang.

Key words: southeastern part of Qinghai-Xizang plateau, snowline, temberline, spatial distribution, climatic condition