海南霸王岭陆均松类热带山地雨林伐后林结构与物种多样性研究

霸王岭林区是海南岛最典型的热带山地雨林分布区.在该区,现存分布面积最广、资源数量最大的是热带山地雨林的各种伐后林.以霸王岭分布最广的以陆均松(Dacridium pierrii)为主的山地雨林的伐后林为对象,研究了其组成、径级、高度结构和物种多样性特征,对比分析了伐后林与原始林以及伐后林不同类型之间的异同.结果表明:原始热带山地雨林经采伐后中小乔木和灌木的优势度增大,而大乔木树种的优势度则明显下降.阳性树种的种类、数量和相对重要性随采伐破坏的程度而增加.伐后林中矮、小树木在林分中比例随采伐破坏的程度增加,而高、大树木,特别是进入主林层树木的比例则随采伐破坏的程度明显下降.从林分测树因子的变化来看,采育择伐和径级择伐的林分要优于大强度择伐和皆伐的林分.原始林的物种丰富度大于伐后林,但其多样性指数和均匀度指数大都小于伐后林.组成上与原始林相似性较大的伐后林是各种择伐后的林分,而皆伐后的林分与原始林在组成上已有很大差别.

Study on Structure and Spec ies D iversity in Post HarvestedTropica lMon tane Ra inforest Dom ina ted byD acridium pie rrii in Bawangling, Ha inan Island

Bawangling forest area is the most typ ical trop icalmontane rain forest area in Hainan island. Due to largescale forest harvesting in the past, most of the extant forests are post harvesting trop icalmontane rain forests, whichhave the greatest resources stock and distribution areas in Bawangling. The widesp read distributed post harvestingtrop icalmontane rain forest p reviously dominated by Dacridium pierriiwas selected as the study object. The composition, size, height structure and species diversity of different post harvested forest standswere studied. Comparisonand analysiswere made among the different post harvesting stands and their virgin old-growth stands. The resultswere as follows: Compared with the virgin stand, the dominance ofmiddle or small trees and shrubs increased whilethe dominance of big trees decreased in the post harvested stands. The species richness, density and relative importance of shade intolerant trees increased with the increase of harvesting intensity or damage degree the forest experienced. The percentages of short and small trees increased while those of the tall and big trees decreased in the postharvested stands, especially canopy trees decreased with the increase of harvesting intensity or damage degree.Based on analysis on the change of some stand factors and in view of forest structure maintenance, itwas concludedthat the harvestingmethods of cuttingwhile tendering and cutting according to size classeswere better than clear cutting and strong intensive cutting. The species richness in virgin stand was greater than those in the post harvestedstands, while the Shannon-Weiner species diversity index and evenness index in the virgin stand were smaller thanthose in the post harvested stands. The post harvested stands formed by selective cutting were more similar in composition than the post harvested stands formed by clear cutting.