四川瓦屋山原生和次生常绿阔叶林的群落学特征

COMMUNITY FEATURES OF THE PRIMARY AND NATURALLY SECONDARY EVERGREEN BROAD-LEAVED FORESTS IN MT. WAWU IN SICHUAN, CHINA

利用野外调查资料 ,比较分析了瓦屋山中山段 (halt15 0 0～ 190 0m)自然恢复的次生和原生常绿阔叶林的群落外貌、群落主要乔木物种组成、高度和径阶结构等特征 .结果表明 :( 1)恢复 42a的次生常绿阔叶林已基本形成中亚热带湿性常绿阔叶的生活型外貌和以中小型单叶为主、草质叶明显的特征 .但与原生的中亚热带湿性常绿阔叶林相比 ,落叶的中小矮高位芽植物明显较多、地面芽和地下芽植物偏少 ;( 2 )次生常绿阔叶林乔木层树种有 6 7种 ,而原生林仅 5 7种 .次生和原生常绿阔叶林乔木层主要优势物种组成相似 ,但次生林优势种更明显 ,并存在较多的处于伴生状态(局部地段还居于优势地位 )的落叶乔木种类 ;( 3)次生林较相同面积上的原生林乔木层的平均胸径DBH<2 .9cm .次生林具有小径阶个体多、大径阶个体少的明显特点 .但两类森林乔木大小结构分布与其它地区的异龄林基本一致 ,均遵从指数分布关系 ;( 4 )次生林 6 40 0m2 内h≥ 3m的乔木有 1199株 .垂直高度h分化不明显 ,hmax=2 2 .8m ,hav仅 9.7m ,而原生林 6 40 0m2 内h≥ 3m的乔木有 10 45株 ,平均高度 12 .8m .次生林缺失VII高度级 ( >2 5m) ,而VI高度级仅 8株 (原生林有 5 5株 ) ,低高度级 (II～IV级 )株数的比例大 ,占总株数的 87.12 % .说明次生林乔木拥?

In order to understand the recovery effect of secondary forest after destroyed for 42 a on community features, the primary and secondary subtropical evergreen broad-leaved forests distributed between 1 500 ～ 1 900 m in Mt. Wawu,Sichuan were investigated by plot method. The differences in community appearance, tree composition, and community structure between the secondary and primary forests were examined. The secondary forest displays more deciduous plants with the types of mesophanerophytes, microphanerophytes, and nanophanerophytes, and less plants with chamaephytes and hemicryptophytes than the primary forest. But the both forests have similar features of leaf size table with dominant moderate/small size leaf-types and with predominant leather unifoliate type leaf. The tree layers of the secondary and primary forests are composed 67 and 57 tree species, respectively. Most dominant trees in the secondary forest are same as those in the primary forest, including Castanopsis platyacantha, Schima sinense, Lithocarpus viridis, L. hance, Acanthapanox evodiafolius var. gricilise and Machilus pingji. But those trees are in more preponderant position and more deciduous tree species as accompanying elements exist in the secondary forest than in the primary. The tree (over 3 m tall) density in the secondary forest is 19 stems per 100 m 2with 3 stems more than in the primary. The average D BH is 18.6 cm in the secondary forest and 2.9 cm less than in the primary. The relation with D BH class and their density obviously displays the feature with more little trees and less big trees, hinting an exponent distribution type in accordance with other relevant research conclusions. The average tree height in the secondary forest is 9.7 m and 2.1 m shorter than in the primary. And the relation with tree height class and their density displays the feature with shorter trees and less tall trees in the secondary forest, implicating more congested and stronger competition among trees than in the primary forest and subsequently self-thinning processing. Comprehensive comparison in community features between the secondary and primary forest suggests that the secondary forest with a 42-year recovery have shaped into broad-leaved and evergreen appearance and entered into broad-leaved evergreen forest stage. It suggests the natural recovery is successful and is an alternative pathway in ecological restoration of broad-leaved evergreen forest. The present results in the paper also indicats community features (such as appearance, tree composition and structure) could be considered as index to detect forest restoration. Fig 2, Tab 4, Ref 35