Abstract:

In this paper, the response of the ecological dynamics and tree-growth to climate change was investigated at the treeline ecotones in Qilian Mountains. The results showed that the young plants (1-30 a age) occupied 80.5% of the total number of trees at the treeline ecotones. The population density increased by 23 times, however the tree limit position in the treeline ecotones was not significantly changed during the past 100 years. In addition, the radial growth of Picea crassifolia showed a steady increase trend in the past 30 years. According to the relationship between radial growth and climate, the radial growth of trees was positively and significantly correlated with mean temperature of the summer and fall, as well as the previous summer and fall, especially the previous fall and June.

Key words: Picea crassifolia, population strucure, tree-ring, climate change, treeline ecotones