云南镇康大雪山常绿阔叶林群落类型的研究

 常绿阔叶林在云南植被中占有重要位置，属于我国的西部类型，镇康大雪山的常绿阔叶林面积大，发育好，保存较完整，是一类具有代表性的中山湿性常绿阔叶林。本文根据常绿阔叶林的外貌、结构、成层性、优势种和生境条件特征的异同进行群落类型的划分。该地区常绿阔叶林分布较南，属于西南季风的前沿，地形复杂，山体较高，树种资源丰富，乔木优势种也较明显，生境湿润，林冠下一般具明显的竹子层片，群落类型多样，单位面积木材蓄积量较高。这类植被从自然保护研究和生产实践上具有重要的价值。

A Study on Community Types of Evergreen Broadleaf Forests in the Daxue Mountain in Zhenkang County, Yunnan Province

The Daxue Mountain in Zhenkang county is situated in the southwest part of Yunnan Province, occupying 24?20′N, 99?06′E. The evergreen broadleaf forests under study are well preserved. They are characterized by complexity of types, abundance of tree species and wide distribution in a wide range of altitudes (from 1900m to 2800m above sea level). They are typical mountain humid evergreen broadleaf forests in the subtropical region of Yunnan.In the paper, according to similarity in community structure, dominant species and habitat condition, these evergreen broadleaf forests have been divided into five community types, They are:1. Lithocarpus echinotholus-Ardisia crispa var. amplifolia community; 2. Cyclobalanopsis glaucoides-Vaccinium bracteatum community; 3. Lithocarpus echinotholus-Ophiopogon grandis community; 4. Lithocarpus echinotholus-Acer sikkimense var. serrulatum community; 5. Lithocarpus echinotholus-Tsuga dumosa community.Stratification in all these communities is obvious. The trees totaling 85 species may be divided into three layers. Some of these species have tropical origin, such as species of the Elaeocarpaceae, Sapotaceae and Proteaceae. The dominant species of tree layer are different from the other mountain humid evergreen broadleaf forests in other places of Yunnan. One of them is the Lithocarpus echinotholus, which is distributed widely in this region. The trees of the upper layer are always mixed with a few deciduous broadleaf trees and the Tsuga dumosa (an evergreen needle tree). Bamboo groves of the species synusia are conspicuous in the undergrowth, which also contains of Chimonobambusa and Pleioblastus. The herb layer is not well developed. The dominant plant lifeforms of this forest are the mesophanerophytes and microphanerophytes, which account for 62.5% of the forest. The trunks of big trees are round and straight, the bases of which often become little buttresses. The timber storage of this forest reaches over 260m3/ha. The natural regeneration of the dominant species is very poor under the canopy, but better at forest-windows or forest-edges.It is suggested that these kinds of evergreen broadleaf forest must be delimited into a natural preserve, so that they may present a principal scientific base for forestry research.