Research On The Composition And Laws Of Plant Community In The Subalpine-alpine Zone On The West Slope Of Changbai Mountain

The ecotone, at an elevation of 1900～2200m on the west slope of Changbai Mountain, dominated by atmosphere and environment is the product from the interaction of biotic and a biotic factors. Betula-tundra transition zone, as the special type of the forest-tundra ecotones, is the unique landscape belt in Changbai Mountain which has important research significance.In this paper, we focus on the plant composition and the community types in different altitudes. In view of the plant distribution on the west slope of Changbai Mountain, plant survey has been carried out by quadrate sampling method. And we assess the importance value of different communities at different altitudes. From the importance value of dominant species in one community at the same elevation, we can get the laws with altitudes.The conclusion shows that the plant composition on the west slope performs richness. As altitude upward shift, it is characterized by the distribution of arbor-shrub-herbaceous and shrub-herbaceous. Different vegetation at different altitudes performs different composition patterns. The same vegetation at different altitudes also performs different. From the environment standpoint, altitude and disturbance are the key factors for the plant communities in Changbai Mountain. As the altitude shifts, the composition and hierarchy transited from simple to complex, and the dominant species from multi to single. With the increase in altitude, shrub layer plants have downward trend, and Rhododendron aureum shows loose, rosette, collective growth, and appears patchy at an altitude of 2180m distribution. However, Herb's abundance, coverage, height and species diversity increased with elevation fluctuating decline. The same as Rhododendron aureum, common in coniferous forests and Betula Ermaii forests, Deyeuxia angustifolia's viability is stronger than the other vegetation, which has intruded upward along tundra.