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.