莽山几种典型低质低效次生林结构及成因分析

Analysis of the Structure Characteristics and Formation Reasons of Several Typical Defective and Low-effect Secondary Forests in Mangshan

在湖南省莽山林区次生林的分布区内 ,设置标准调查样地 ,测定生态环境因子 ,调查植物群落、林分状况及次生林成因 .根据该区林分的建群种和有指示意义的灌木种类 ,在莽山林区选择 5个典型低质低效次生林即 :( 1)硬斗石栎、山鸡椒、南岭箭竹为主 ;( 2 )杉木 (萌芽 )、红楠、东方古柯、南岭箭竹为主 ;( 3 )马尾松、金毛石栎、鹿角杜鹃、苦竹为主 ;( 4 )马尾松、铁芒萁为主 ;( 5 )马尾松无灌草次生林 .分别对这 5种类型低质低效林分的结构特征和成因进行分析 ,从而可知低质低效次生林的成因是 :( a)自然条件差 ,如高寒、坡陡、土壤贫瘠 ;( b)经营方式不合理 ,如缺乏有效的抚育间伐 ,人为干扰破坏 .

By using the sample plots of several typical defective and low effect secondary forests distributed in Mangshan, Hunan Province, the ecological environment factors, the forest community, the status of the stands and the reasons of the secondary forests are investigated. According to the dominant plants and indicative shrubbery species in the forests, five typical defective and low effect secondary forest types are selected as the following:① community mainly constituted by Lithocarpus hancei, Litsea cubeba and Sinarundinaria basihirsuta;②community mainly composed of Cunninghamia lanceolata, Machilus thunbergii, Erythroxy kunthianum and Sinarundinaria basihirsuta; ③community mainly constituted by Pinus massoniana,Lithocarpus chrysocomus,Rhododendron latoucheae and Pleioblastus amarus; ④community mainly comprising Pinus massoniana and Dicranopteris dichotoma; and ⑤community mainly constituted by nothing but Pinus massoniana. After analyzing the formation reasons and structure characteristics of the five forest types respectively, the results show that high mountains, stiff slopes, cold climate and infertile soil are the main natural reasons, and others reasons are unreasonable management, no treatment or thinning for the forest, manly disturbance and destruction.