中文摘要：

斜坡方面在山区的森林的发展和分发有重要效果，特别在干旱、半干旱的区域。用 SPOT5 图象和 1:50,000 DEM ，这份报纸数字地提取并且分析山区的具球果的森林的空间信息(主要 Qinghai 云杉)，并且从而探索上面、更低的限制和具球果的森林的高度的范围怎么变化并且具球果的森林的区域怎么与有在 Helan 山的所有方面的年度曝晒是相关的。结果显示出那：1 ) 在东方胁腹，具球果的森林的更低的限制在 1,600 m 和 2,000 m 之间是 a.s.l 和 3,000 m a.s.l；在西方的胁腹，具球果的森林的更低的限制在 2,000 m 和 2,300 m 之间是 a.s.l 和 3,100 m a.s.l 2 ) 具球果的森林的高度的范围分别地是 8061,435 m，为东方胁腹的 4381,140 m 和西方的胁腹。3 ) 具球果的森林的区域与方面呈现正常分布，并且它与年度曝晒有一种靠近的关系。在这纸份量上开发的这个分发模型在干旱、半干旱的土地在具球果的森林的分发上揭示斜坡方面的重要效果。

英文摘要：

Slope aspect has significant effect on the development and distribution of montane forest, especially in arid and semiarid regions. This paper, using SPOT5 images and 1：5o,ooo DEM, digitally extracts and analyzes the spatial information of montane coniferous forest （mainly Qinghai spruce）, and thereby explores how the upper and lower limits and the altitudinal range of coniferous forest vary and how the area of coniferous forest is related with annual insolation with all aspects in the Helan Mountains. The results show that： 1） In the eastern flank, the lower limit of coniferous forest is between 1,6oo m and a,ooo m a.s.l., and the upper limit between 2,800 m and 3,ooo m a.s.1.; in the western flank, the lower limit of coniferous forest is between a,ooo m and 2,300 m a.s.l., and the upper limit between 9,80o m and 3,1oo m a.s.1.2） The altitudinal ranges of coniferous forest are 8o6-1,435 m, 438-1,14o m for eastern flank and western flank, respectively. 3） The area of coniferous forest takes on a normal distribution with aspect, and it has a close relationship with annual insolation. This distribution model developed in this paper quantitatively reveals the significant effect of slope aspect on the distribution of coniferous forest in arid and semi-arid land.