北亚热带栎树混交林空间结构特征分析

Spatial Structure of Quercus Mixed Forest in Northern Subtropical Region

运用传统林分结构因子配合混交度、角尺度、大小比数和开敞度4个林分空间结构参数,对江苏盱眙森林群落的空间结构特征进行了分析。结果表明:1)调查林分物种多样性丰富,栓皮栎、檞栎、麻栎在株数和断面积占有明显优势,是乔木层的优势种,树高>18m为主林层,但优势种的生长优势不明显;2)林分平均混交度为0.62,处于强度混交状态;林分平均角尺度为0.48,属随机分布;林分平均大小比数为0.49,有49%的林木处于优势状态;林分平均开敞度为0.451,林木生长空间充足;3)栓皮栎由于生长优势不明显,在演替过程中优势度会有所下降,黄连木、檞栎会成为该地区的优势树种。

In order to understand the stand structure of mixed forest in northern subtropical region,the spa- tial structure of forest community in Xuyi,Jiangsu Province was analyzed by using traditional stand struc- ture indices and four spatial structure indices of mingling, angle index, neighborhood comparison and open- ing degree. The results were reported as follows. 1） The species diversity of the mixed forest was rich, Quercus variabilis,Q, aliena and Q. acutissima had the obvious superiorities in the number of trees and basal areas, being the dominant species of the trees layer, the tree heights of these species was higher than the main storey （18 m） of the forest,while the growth vigor however,was not good. 2） The degree of aver- age mingling of the stand was 0.62, belonging to strong mixed state. The angle index was 0.48, which was within the random distribution. The neighborhood comparison ratio was 0.49,and 49 % of the trees in the stand were dominant ones. The average opening degree was 0. 451,which displayed that the growth space of most trees in the forest was sufficient. 3） The growth advantage of Q. variabilis was not significant,which would decline in the succession process,Pistacia chinensis and Q. aliena would become the dominant species.