地球上植被的大型分布,明显地呈现地带性变化。平地上表现为水平地带性,包括纬度地带性和干燥度地带性;山地上表现为垂直(地)带性,就是所谓“三维空间”分布现象。我国地广山多,自然条件复杂,研究山地植被的分布规律不但具有理论意义,而且也富有实践意义。

On account of vast territory and complex physico-geographical conditions as well aagreat human impacts, the distribution of mountain vegetation in China is very compli-cated. Yet, law of zonation still holds true. The structure and character of mountainvegetation change along two directions, i.e., from south to north and from east to west.In the eastern part of China altitudinal vegetation-belt spectrums change mainlyfrom south to north.1. Warmth-like types of altitudinal vegetation-belt spectrums being replaced bycold-resistant types with alternation of basic vertical vegetational belts from evergreenbroad-leaved forests to deciduous needle-leaved forests.2. Diminution of number of altitudinal belts and simplification of their structures.3. Lowering down of altitudes of altitudinal vegetational belts. On mountains inwestern part of subtropical zone lies the highest altitude of timberline in the world, witha maximum altitude of over 4,400 m above the sea level. It lowers down towards northby over 100 m per degree of latitude.4. Occurrence of dominant belts in vertical profiles of mountain vegetation de-pends upon the nature of horizontal zones. The dominant belts in typical geographicalzones are certainly the basic vertical vegetational belts. And in transitional zones theyoccur above the basic vertical belts.While in the arid and semi-arid western part of China, changes of altitudinal vege-tation-belt spectrums are quite different. They take place chiefly from east to west. Itis worthwhile mentioning that structures of vegetation-belt spectrums are very simpli-fied, steppes and deserts occupy the dominant position on mountains and all altitudinalvegetational belts ascend in this direction.