| Larix chinensis populations distributed in a wider area, but mainly distributed in Mt.Taibai, which was the the highest peak in Qinling mountain range. They arrayed like strips both sides of the ridges between altitude 2500 and 3500 meters. In other areas of Qinling Mountain, such as Changqing National Nature Reserve in Yang County, Mt.Guangtou in Chang'an borough in Xi'an City and Niubeiliang National Nature Reserve in Zhashui County, L. chinensis populations distributed sporadic. In this article, Mt.Taibai and Mt.Guangtou were selected to be samples. The spatial pattern characters of L.chinensis populations in the two sample areas were studied. The results illustrated the spatial pattern characters and the dynamic changing progress of L.chinensis populations in different habitat in Qinling Mountain. Then, the biology factors (including innerspecis and interspecis relationship) and the environment factors, which as the key factors affected the spatial pattern characters of L.chinensis populations, were analysed and the reasons leading to the the spatial pattern characters of L.chinensis populations were discussed.Field data were sampled by the method of contiguous grid quadrate when studing the spatial pattern characters of L.chinensis populations. The fractal characters of L.chinensis populations in Mt.Taibai and Mt.Guangtou were studied by boxing-counting dimension and information dimension. The results of Mt.Taibai, higher boxing-counting dimension (1.8087) and information dimension (1.7931), reflected that there was a higher spatial occupational degree in L. chinensis populations. The results of Mt.Guangtou, higher boxing-counting dimension (1.8247) and lower information dimension (1.2428), reflected that there was a higher spatial occupational degree in L.chinensis populations, but the instruction was comparative simple. The spatial pattern types of L.chinensis populations in two sample areas were studied by the following methods: dispersal index, Moore's^) test, Morisita's pattern index, Hopkins and Skellams' A index, Taylor method and Iwao method. The results showed that L.chinensis populations clumped totally and, in Mt.Taibai sample areas, clumped in the three different age stages (0-25, 25-50 and over 50 years) too. Then, the pattern scalewas studied by Greig-Smiths' mean variance. The figure of pattern scale showed that L.chinensis populations clumped in 128 m and 512 m in Mt.Taibai and the different age groups clumped in different scales. In Mt.Guangtou, L.chinensis populations clumped in 50 m2 and 400 m2. Finally, the pattern intensities were researched by Kershaw's PI index and some other indexes. The results indicated tha the distribution of L. chinensis was not even and the pattern intensities were decreasing with the age increasing and tended to reduce with the area increasing. The spatial pattern characters of L.chinensis populations maybe were the response to the environmental factors.The relations of the population density and the pattern intensity of L.chinensis in different scales were analysed by multinomial regress. The results showed that the current spatial pattern of L. chinensis populations could be explained by the innerspecis competitive intensity in smaller scale. The species in communities of. L.chinensis both in Mt.Taibai and Mt.Guangtou, and their interspecific relationship were studied by using Fisher' s exact test for a 2X2 contingency table. In addition, Pearson's correlation coefficient was applied to test for correlation between species. The results showed that the interspecific relationships of L. chinensis communities were simpler, but more abundant in herb layer and less in shrub layer. In arbor layer, L.chinensis and Abies fargesii obviously showed their significant negative covariation. Drawing a conclusion, there was no obvious pertinence between the interspecis relationship and the population spatial pattern of L.chinensis. So, the interspecis relationship would be inapplicable to explain how forming the current spatial pattern of L.chinensis populations.The...
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