| The approach of the"space instead of time"was adopted to study the structure of communities, which belong to different successive stages and the diversity of plants in the communities. The results are as follows:(1)The secondary communities in this area can be divided into three successive stages which are shrub layer community, pinus forest community and pine broad-leaved mixed forest community on the basis of the order of succession.(2) Certain differences existed in the composition of the species of plants in different successive stages. There are 42 kinds of plants in the 9 sample fields which are studied.①The richness index of the tree layer in the stages of pine broad-leaved mixed forest and pinus forest are 1.67 and 0 respectively, which shows significant differences. The richness index of the shrub layer in the stages of pine, pinus forest and secondary shrub are 1.55, 2.17 and 2.8 respectively which shows significant differences as well. The index of the vegetation layer in the three stages are 0.89, 0.69 and 0.56 which shows no significant differences.②The Shannon-winner index of the tree layer in the stages of broad-leaved mixed forest and mixed coniferous are 0 and 0.59 respectively which shows significant differences. The index of the shrub layer in the three stages are 0.66, 0.89 and 1.68 respectively which shows Significant differences as well, The index of the vegetation layer are 0.66, 0.89 and 1.68m, which shows no significant differences.③The evenness index of the tree layer in the stages of pinus forest and mixed coniferous are 1.02 and 1.47, which shows significant differences. The index of the shrub layer in the stages of secondary shrub, pinus forest and mixed coniferous are 1.43, 1.68 and 1.88, which shows significant differences. The index of the vegetation layer in the 3 stages are 1.47, 1.35 and 1.44, which shows no significant differences. The results shows out of the 3successive stages the richness index, Shannon-winner index and the evenness index of the arbor and shrub in the stages of mixed coniferous are the largest. The results also show that the diversity if plants, the richness and the evenness index of the communities increased because of the succession the mountains of Zongyang.(3)In general, the vertical structure of the three stages in the mountains of Zongyang is a little simple. There isn't tree layer in the stage of secondary shrub. The tree layer is all made up of pinus forest in the stage of pinus forest. In the stage of mixed coniferous, the tree layer is made up of the Pinus massoniana, Platycarya strobilacea and Liquidambar formosana. The results show the vertical structure gradually becomes complex because of the succession.(4) Because of the succession, great changes took place in the ecological environment in the community.①Significant differences existed in the daily courses of light intensity which are measured at the height of 1.7m, 1.2m and 0.3m away from the ground. At the same period, all of the light intensity is secondary shrub> pinus forest > pine broad-leaved mixed forest. The results show that the weakenness of light intensity becomes more obvious when the measured height becomes lower.②Most of the differences of the daily courses of the temperature ware not significant but the others were significant. In general, the difference in the daily courses of the temperature in the vertical direction was not obvious. The temperature in the community is usually lower than that outside the community. In the community of mixed coniferous the daily courses of temperature is a little slower than that in the other two communities.③The humidity level which is measured at the height of 1.7m, 1.2m and 0.3m becomes higher gradually, but the differences are not obvious.④In the same successive stage the soil bulk density of different layers gradually becomes larger. The trend is secondary shrub> pinus forest> pine broad-leaved mixed forest.⑤In the same successive stage the soil moisture of different layers gradually becomes larger from the top to the bottom.⑥In the same layer the trend of soil moisture of different successive stages is pine broad-leaved mixed forest > pinus forest > secondary shrub.⑦In the same successive stage water stable aggregate(>0.25mm) of the soil of different layers gradually becomes smaller from the top to the bottom, while in different successive stages the trend is pine broad-leaved mixed forest > pinus forest > secondary shrub.⑧In the three successive stages the differences in the pH value of soil of different layers ate not obvious. In the same successive stage the organic matter content of different layers reduced from the top to the bottom, in the different successive stages the trend of the organic matter content is pine>pinus forest>secondary shrub.⑨The HN, available P, available K in the soil increased when the layers of soil becomes larger. In the same layer of soil in the different successive stages the trend of content of HN, available P and available K is pine broad-leaved mixed forest > pinus forest > secondary shrub.(5) The results of the correlation analysis on the diversity and soil properties in different successive stages showed that certain correlations were found between the richness index, Shannon-winner index and evenness index of different layers in the communities and the soil properties of different layers to some extent.①Good correlations were found between the richness index of the tree layer and seven factors including the soil bulk indensity (0-10cm), moisture, the content of water stable aggregate(>0.25mm), the content of organic matter, TN, available P and available K. Significant good correlations were found between the index and the HN in the soil. Significant good correlations were found between the richness index of the shrub layer and the 8 factors mentioned above. Significant good correlations were found between the richness index of the vegetation layer and the 5 factors including the bulk indensity, water stable aggregate(>0.25mm), the organic matter, HN and available K, while good correlations were found between the index and the other 3 factors including the soil moisture, TN and available K. Significant good correlations were found between the Shannon-winner index of the tree layer and the 8 factors except HN. Good correlations were found between the index and HN. Significant correlations were found between the Shannon-winner index of the shrub layer and all the 8 factors. Significant good correlations were found between the evenness index of the tree layer and all the 8 factors. What's more, negative correlations were found between the index and the soil bulk indensity. Good correlations were found between the index of the shrub layer and all the 8 factors except TN, available K and soil moisture.②Significant correlations were found between the richness index of the tree layer and the soil moisture (10-20cm) and TN, while good correlations were found between the index and the bulk indensity. Significant correlations were found between the richness index of shrub layer and all the 8 factors except organic matter and bulk indensity, while negative correlations were found between the index and the bulk indensity. Significant correlations were found between the richness index of the vegetation layer and available K, while good correlations were found between the index and the 3 factors including the soil moisture, HN and available P. The Shannon-winner of the tree layer and two factors which are 10-20cm and TN, while good correlations were found between the index and the other 5 factors including the bulk indensity, organic matter, HN, available P and available K. Significant correlations were found between the Shannon-winner index of the shrub layer and all the 8 factors except organic matter and available P. Significant correlations were found between the evenness index of the tree layer and the four factors including 10-20cm, water stable aggregate(>0.25mm), HN and available K, while good correlations were found between the index and the other 4 factors . What's more, negative correlations were found between the index and the bulk indensity. Good correlations were found between the evenness index of the shrub layer and the available P.③Significant correlations were found between the richness index of the tree layer and 2 factors which are the soil moisture and available K (20-30cm). Significant correlations were found between the index of the Shannon-winner index rub layer and the soil moisture (20-30cm). Significant correlations were found between the Shannon-winner index of the tree layer and the soil moisture. Good correlations were found between the index and 2 factors which are water stable aggregate(>0.25mm) and HN. Significant correlations were found between the Shannon-winner index of the shrub layer and the soil moisture( 20-30cm). Significant correlations were found between the evenness index of the tree layer and the soil moisture (20-30cm). Good correlations were found between the index and available K. Good correlations were found between the index of the vegetation layer and the organic matter in the soil (20-30cm).
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