Abstract: In this paper,the fractal characters of Larix chinensis populations in Qinling Mountain were studied by contiguous grid quadrate sampling method and by boxing-counting dimension and information dimension.The results showed that the high boxing-counting dimension (1.8087) and information dimension (1.7931) reflected a higher spatial occupational degree of L.chinensis populations.Judged by the dispersal index and Morisita's pattern index,L.chinensis populations clumped at three different age stages (0～25,25～50 and over 50 years).From Greig-Smiths'mean variance analysis,the figure of pattern scale showed that L.chinensis populations clumped in 128 m² and 512 m²,and the different age groups clumped in different scales.The pattern intensities decreased with increasing age,and tended to reduce with increasing area when detected by Kershaw's PI index.The spatial pattern characters of L.chinensis populations may be their responses to environmental factors.

Key words: Oasis-desert ecotone, Vegetation coverage, Soil factors, Spatial heterogeneity