福建武夷山自然保护区地形对毛竹(Phyllostachys pubescens)林分布的影响

Effects of topographical factors on distribution of Phyllostachys pubescens in Wuyishan Nature Reserve, Fujian Province, China

用PC ORD 4 .0软件对保护区内 31个毛竹 (Phyllostachyspubescens)林样方进行聚类分析 ,把毛竹林划分成9类。利用保护区 1980年航空相片、1998年和 2 0 0 0年LandsatTM卫星影像 ,并结合保护区森林资源调查资料 ,绘制武夷山保护区毛竹林分布图。利用保护区 1 5 0 0 0 0的地形图数字化 10 0m等高距生成数字高程模型 (DEM ) ,并从中获取海拔、坡向、坡度等地形参数 ,对毛竹林分布进行空间叠加分析。结果表明 :保护区内毛竹纯林和毛竹—甜槠 (Castanopsiseyrei)林面积最大 ,分别占毛竹林总面积的 4 0 .6 %和 2 0 .3%。分析毛竹林与海拔的关系时得出 ,海拔 5 0 0 - 70 0m范围内毛竹林面积最大 ;随着海拔升高 ,毛竹林面积逐渐减少 ,Shannon Wiener指数 (H′)增加 ;毛竹最大胸径减小。毛竹在东南坡和西北坡分布的面积比例最大。随着坡度的增加 ,毛竹分布的面积减少。

Based on 31 sample plots, 9 community types of bamboo (Phyllostachys pubescens) forest from Wuyishan Nature Reserve, Fujian Province, were identified by cluster analysis in PC-ORD 4.0. The distribution of these 9 types was mapped based on the distribution map derived from aerial photos (1980) and two sets of Landsat TM (Thematic Map) images (1998, 2000) integrated with the data of the forest inventory in the whole reserve. Topographic features such as altitude, slope and aspect were derived from a Digital Elevation Model (DEM) created by digitizing the contour map in 100 m intervals (1 50 000 ). These features were then applied to spatial overlay analysis of bamboo distribution. The pure bamboo forest (40.6%) and Phyllostachys pubescens - Castanopsis eyrei bamboo forest (20.3%) were the two major types of bamboo forest in Wuyishan Nature Reserve. Maximum area of bamboo forest was recorded at the altitude of 500-700 m a.s.l. The proportion of bamboo forest within each altitudinal band declined with increasing altitude. Shannon-Wiener index (H′) of tree layer increased and diameter of breast height (DBH) decreased along the altitudinal gradient. The area of bamboo forests on the southeast and northwest slopes were larger than on other exposures. The area of bamboo forest decreased with the increasing slope.