Abstract: 【Objective】 To understand the quantitative correlation between spatial distribution and topographic factors (elevation, aspect,slope) of natural arbor forests in western Tianshan Mountains, and to provide scientific basis for the protection and management of forest resources.【Method】 The natural arbor trees in the mountain area under the jurisdiction of State-owned Forest Administration in the Western Tianshan Mountains were chosen as the testing materials and based on DEM data, Landsat data and the field investigation for forest resources, a quantitative study on the spatial distribution of natural arbor forest in the western Tianshan Mountain was carried out by RS and GIS technologies. 【Result】 The natural arbor forest in the western Tianshan Mountain was mainly distributed in the area of 1,200 -2,500 m above sea level, and the distribution index was 96.19%. The trees were mainly distributed in shady and semi-shade slops (the north, northeast, northwest slopes and part of east and west slopes), and the distribution index was 88.72%; most of the natural arbor forests grew in the slope from 15° to 55°, including ramp, steep and acute slopes and part of dangerous slope, among which the distribution index of the steep slope was the largest. The tree species in the study area were Picea schrenkiana, Populus tremula, Betula pendula, Armeniaca vulgaris and Malus sieversii. Among them, P. schrenkiana covered the largest distribution area and the widest elevation range, followed by P. tremula and A. vulgaris. The suitable growing areas for P.schrenkiana, P. tremula and A. vulgaris were within sea levels between 1,800-2,400 m, 1,400-2,000 m and 1,000-1,600 m.【Conclusion】 P. schrenkiana, P. tremula and A. vulgaris are the main natural tree species in western Tianshan Mountains. They are mainly distributed on the shady and semi-shady slope aspects and slopes from 15 to 55°of the middle high mountains and sub-alpine areas. In forest tending and regeneration, the suitable tree species should be selected according to the topographic conditions, thus ensuring the survival rate of tree seedlings and promoting the rapid regeneration of arbor forests.

Key words: the western Tianshan Mountains; 3S technology; the natural arbor forest; spatial distribution; topographic factors

摘要： 【目的】研究天山西部山区天然乔木林分布规律与地形因子(海拔、坡向、坡度)的定量关联,为森林资源的保护与管理提供科学依据。【方法】选取天然乔木林为对象,通过3S技术对Landsat数据进行分类,基于DEM数据生成地形因子,结合森林资源二类调查数据,定量研究天山西部山区天然乔木林的空间分布规律。【结果】天山西部山区天然乔木林主要分布在海拔1 200~2 500 m的区域,分布指数96.19%;坡向上主要分布在阴坡、半阴坡(包含北坡、西北坡、东北坡全部以及东坡、西坡部分区域),分布指数88.72%;坡度上主要分布在坡度≥15~55°,包括斜坡、陡坡和急坡以及险坡的部分区域(≥45~55°),其中在陡坡的分布指数最大。研究区树种有雪岭云杉(Picea schrenkiana)、欧洲山杨(Populus tremula)、疣枝桦(Betula pendula)、杏(Armeniaca vulgaris)和天山野苹果(Malus sieversii),其中以雪岭云杉分布面积最大,海拔范围最广;其次为欧洲山杨,第三为杏;适宜雪岭云杉生长的海拔区域为1 800~2 400 m,欧洲山杨适宜生长区为1 400~2 000 m,杏适宜生长区为1 000~1 600 m。【结论】天山西部山区天然乔木林树种以雪岭云杉、欧洲山杨和杏为主,主要分布在中山—亚高山的阴坡、半阴坡且坡度为≥15~55°的区域。森林抚育、更新时应根据地形条件选择适宜树种,保证树种幼苗成活率,促进乔木林快速更新。

关键词: 天山西部, 3S技术, 天然乔木林, 空间分布, 地形因子