基于空间信息技术的香榧适生环境因子分析

香榧系第三纪孑遗植物，为我国特有的珍贵经济树种，是我国近年来发展较快、经济效益最好的经济林树种之一.研究香榧特有的适生环境特征将为香榧的引种、扩种和区划提供理论依据，对其产业化发展和可持续利用具有重要意义.基于空间信息技术的强大功能，利用香榧核心产区——浙江省诸暨市７个村的高分辨率IKONOS遥感影像、数字高程模型(DEM)以及土壤、地质、气象和实地调查等资料，采用主成分分析方法对研究区的生境因子进行了综合分析.结果表明：研究区香榧对海拔、坡度和坡向等因子具有高度选择性;96.22%的香榧分布在海拔300～600 m的高度带上，97.52%的香榧分布在坡度<30°的坡地上，74.43%的香榧分布于阳坡和半阳坡.主成分分析结果显示，影响香榧生境的生态因子依次为水分、热量和土壤养分.香榧独特的生物生态学特性表明，水分可能是影响香榧生境形成的最重要的生态因子之一.

Habitat factor analysis for Torreya grandis cv. Merrillii based on spatial information technology.

Torreya grandis cv. Merrillii, a tertiary survival plant, is a rare tree species of significant economic value and expands rapidly in China. Its special habitat factor analysis has the potential value to provide guide information for its planting, management, and sustainable development, because the suitable growth conditions for this tree species are special and strict. In this paper, the special habitat factors for T. grandis cv. Merrillii in its core region, i.e., in seven villages of Zhuji City, Zhejiang Province were analyzed with Principal Component Analysis (PCA) and a series of data, such as IKONOS image, Digital Elevation Model (DEM), and field survey data supported by the spatial information technology. The results showed that T. grandis cv. Merrillii exhibited high selectivity of environmental factors such as elevation, slope, and aspect. 96.22% of T. grandis cv. Merrillii trees were located at the elevation from 300 to 600 m, 97.52% of them were found to present on the areas whose slope was less than 30°, and 74.43% of them distributed on sunny and half- sunny slopes. The results of PCA analysis indicated that the main environmental factors affecting the habitat of T. grandis cv. Merrillii were moisture, heat, and soil nutrients, and moisture might be one of the most important ecological factors for T. grandis cv. Merrillii due to the unique biological and ecological characteristics of the tree species.