关键词: 阴山山脉, 天然侧柏林, 群落特征, 径级结构, 演替序列

Abstract

Natural Platycladus orientalis forests in the Yin Mountains are the northwestern boundary of natural Chinese P. orientalis forests and also one of the most important forests in the Yin Mountains, with respect to erosion prevention, soil conservation, water conservation, and habitat improvement. This study examined details about the characteristics of the population, community, and distribution of natural P. orientalis forests, to allow for better management as well as to provide a theoretical basis. Natural P. orientalis forests in Daqing Mountain and Wula Mountain were selected as the research subjects, and through quadrat investigations, were divided into 6 associations. Characteristics of the flora and the structure were analyzed. We also discussed the diameter structure of each association of P. orientalis and the distribution succession series between associations. The main results are as follows: (1) There were 96 vascular plants belonging to 70 genera of 30 families found in the natural P. orientalis forests, and the geographic components of species contained 8 types and 18 subtypes, which were mainly distributed in the East Pan-North Pole, followed by East Asia; (2) From the analysis of community structure, well-developed natural P. orientalis forests were characterized by a tree layer and herb layer, however the shrub was sensitive to interference, and coverage was generally lower in areas with more human interference, and could even disappear; (3) The diameter structure of P. orientalis followed a normal distribution which is a stable community type, and average plant height increased with the diameter overall growth model; (4) Due to strong interference and harsh habitats, the average diameter of P. orientalisis was small, and they were also more bifurcation which is not suitable for timber forests. We suggest regarding these natural P. orientalis forests as ecological and provenance forests.

Key words: Yin Mountains, natural Platycladus orientalis forests, community characteristics, diameter structure, succession series