安徽肖坑亚热带常绿阔叶次生林的结构特征

Stand Structure and Successional Dynamics of A Subtropical Evergreen Broad-leaved Forest in Xiaokeng,Anhui Province

对安徽老山自然保护区肖坑流域18、36、40、48和65年生的亚热带常绿阔叶林群落结构特征和树种多样性进行了调查分析。结果表明,5块样地内共出现树种26种,分属于15科21属,以壳斗科和金缕梅科为主;群落垂直结构简单,灌木层和草本层不甚明显。按森林演替方向从幼龄林到中龄林,林分密度逐渐下降,40年生以上的林分密度相差不大;幼龄林(18和36年生)中大径级植株(D≥20cm)仅占总株数的3%,中龄林(40年生以上)的占30%,这些大胸径植株的胸高断面积分别占林分总胸高断面积的8.8%～20.6%(幼龄林)、61.9%～70.7%(中龄林)。肖坑亚热带常绿阔叶林的树种多样性较低,中龄林林分平均多样性指数和均匀度指数分别为1.79和0.53;依据优势度划分,该地区常绿阔叶林的优势科为壳斗科,优势种为甜槠、苦槠、青冈和东南石栎。从种群的演替趋势来看,苦槠和东南石栎属发展型、演替中期种;而甜槠和青冈属成长型、顶极群落的主要种。

A survey was conducted to study the structure and tree species diversity of a subtropical evergreen broad-leaved forest in Xiaokeng, Laoshan Nature Reserve, Anhui Province. A total of 26 tree species （DBH≥3.0 cm） were recorded within 5 plots in the forest, which belong to 15 families and 21 genus. Fagaceae and Hamamelidaeeae were dominant families. The vertical structure of the forest was simple, without obvious shrub and herb layers. The stand density ranged from 4 152 （18-year-old） to 2492 （65-year-old） stems·hm^-2.The trees with DBH≥20 cm accounted for 3% of the total number in the young stands （18-and 36-year-old） and 30% in the medium-aged stands （over 40-year-old）, while the basal area of large trees occupied 8.8%-20.6% and 61.9%-70.7% of the total basal area for different successional phases of young （ 18-and 36-year-old） and medium-aged （ over 40-year-old） slands, respectively. The diversity index and evenness index of tree speeies in medium-aged stands averaged 1.79 and 0.53. The dominant family for the forest was Fagaceae in terms of importance value, and the dominant tree species were Castanopsis eyrei, C. sclerophlla, Lithocarpus harlandii, and Cyclobalanopsis glauca. In view of successional trend, C. sclerophlla and L. harlandii were development type and successional mid-phase species, while C. eyrei and C. glauca were growing type and climax species.