Dynamics change of Betula ermanii population related to shrub and grass on treeline of northern slope of Changbai Mountains
长白山北坡林线灌木草本植物与岳桦的动态关系

We selected the treeline of northern slope of Changbai Mountains as study area. The diameter-class structure of Betula ermanii population and ecological important values of shrub and grass were investigated on 125 quadrats. The dynamics changes of Betula ermanii population and 8 plants of shrub and grass were revealed using conventional statistics and hierarchical cluster analysis. The relationship between population dynamics and plants changes was evaluated using correlation analysis. The results showed that population expansion of Betula ermanii drove the shifts of shrub and grass belonged to forest community. Treeline shift was not only tree change, but also forest community invaded tundra community. The ecological niche of tundra community was excluded by forest community. Moreover, the change difference among various compositions was very obvious. The asynchrony appeared during replacement process of varied plants due to the distinction of ecological competitive and status in community.