Community Structure of a Dynamical Plot of Picea crassifolia Forest in Qilian Mountains, China
According to Chinese forest ecosystem dynamic monitoring plot setting method and international forest ecology large plot construction technical standards, a 10. 2 hm2 Picea crassifolia forest dynamic monitoring plot was established in the Qilian Mountains Nature Reserve in 2010 and 2011. The 19 927 woody plants with DBH (diameter at breast height) greater than 1 cm at the plot were surveyed based on positioning survey method, and the community characteristic was analyzed. (1) The layer structure difference is obvious for the P. crassifolia community, and it can be divided into tree layer, shrub layer, herb layer and bryophyta layer. The tree layer is the main layer of the community, and its vertical structure is more complex than the shrub layer and herb layer, and the bryophyta layer is also well developed. (2) The diameter structure of the P. crassifolia community is obviously an "inverted-J" form, the DBH of the individuals is concentrated in 1 - 5 cm and 21 - 25 cm, which account for 91. 42% of the total individuals, so regeneration of the P. crassifolia population is good. (3) The height structure of the P. crassifolia individuals with DBH greater than 1 cm is single-peak form, and the height of the main individuals is less than 6 m, which account for more than 60. 00% of the total individuals. So the height of the P. crassifolia individuals is relatively low, and young trees are much, mid trees hold a certain proportion, and big trees are little. There is a significantly quadratic function relation between the tree height and the DBH of the P. crassifolia (P＜ 0. 05). (4) The spatial distribution of the P. crassifolia individuals displays obviously a clustering distribution pattern. The point pattern analysis of small trees, mid trees and big trees of the P. crassifolia community shows that the clump intensity of the P. crassifolia population reduces with the increasing of the population age, and the congregation distribution turns into random distribution, which displays obviously a diffusion trend. There is no obvious spatial heterogeneity for spatial distribution of the P. crassifolia individuals, and 2 534 big trees of the P. crassifolia community are randomly distributed in the large plot, showing no significant human interference.
NETL
NSTL
万方数据
维普
