Size Structures and Spatial Patterns of Populus Cathayana Populations along Elevation Gradient in Xiaowutai Mountain of Hebei Province
To show the impact of the environmental change on Populus cathayana populations, mean diameters at breast height ( DBH), population densities, size structures and spatial distribution patterns of P.cathayana populations were investigated along an altitudinal gradient ( 1 400 - 1 700 m) in Xiaowutai Mountains.The results showed that the trend of mean DBH of P.cathayana populations was showing “N” type along the altitudinal gradient, and had the minimum value at altitude 1 600 m.The variation of densities along the altitudinal gradient was contrary to the change of mean DBHs.Meaningwhile, the size structures of P.cathayana populations indicated a growth-state distribution along the altitudinal gradient except a decline-state distribution at 1 700 m.Furthermore,by calculating Morisita index and Dispersal index, we found distribution patterns of P.cathayana populations were mainly random and even, and 10 m × 10 m was the appropriate block size for analyzing the spatial pattern of P.cathayana population.Moreover, age structures of P.cathayana populations had an impact on spatial distribution patterns of P.cathayana populations through analyzing distribution pattern of different size classes in P.cathayana populations.In addition, our results indicated that temperature was the main environment factor which caused the differences of P.cathayana populations at different altitudes by analyzing environment factors.
Populus cathayanapopulation structureelevation gradientspatial pattern
NETL
NSTL
万方数据
维普
