The Study Of Community Structure Feature And Community Stability Of The Typical Protection Forest Community In Yan-ting County

The community structure and stability of different types of protection forest communities are in the study of Yan-ting county: To probe deeply the characteristics in Yan-ting county for different types of community structure and the present situation of plant population. In order to provide scientific rules for this area where species diversity will be protected and stable artificial protection forest belt will be built. This research is directed to analyze the characteristics of species diversity of all the plant population and forest floors in this area on the base of many methods. Meanwhile, it studies the stability of forest communities by using many index. The result indicates that:(1)There are in all communities including38families59categories65species, trees including5families5categories6species, shrubs including18families21categories26species, herb including20families35categories36species. The species of the trees is rare while there are always important families in the forests of shrubs and herbs.(2)There are several dominant species and second dominant species in each community and forest floor.In the artificial protection forest, it often takes on relative pure community whether in trees or in shrub and herb floors, while in the natural forest, there is no pure community.(3)The general distribution of the arbor layer species don’t conform to the frequency distribution law while the herb and arbor do. The shrub and arbor have their own eminent major species and Pielou, Alatolo index is high.(4) The highness structure of all the communities are not reasonable. The Cssd of the pure forests is lower than the mixed ones, and the CsR(%) of the nature forests is higher than the artificial ones.(5)The arbor play an important role in the species diversity, the promoting on species diversity of shrub to herb, arbor to herb and the suppression of herb to the whole community is not conspicuous.(6)The water, nutrient features and the validity of nutrient in soil is more correlative with the species diversity than any other factors.(7) The age structure of all the arbor layers are agree with their species diversity, which are both unreasonable. It suggests that the major species of all the arbor layer will be instead of by other species in the near future, and the arbor layers of all the community are not stable. The seeding station is not good and there are few individuals of adult trees in area.(8) The research of stability of community on the basis of M. Godron index suggests that ratio between species percentage and accumulative frequency in the eight communities and the intersecting point coordinate of the straight line y=-x+100are all far from the stable intersecting point coordinate, all will be on the unstable stage.(9) It evaluates comprehensively the stability of protection forest community applying membership function in fuzzy mathematics and taking advantages of the mentioned seven indexes. The result suggests that the relatively stability of the area in the natural community is larger than the artificial one. The full sequence is:Community Ⅶ (0.6576)>Community Ⅷ(0.6515)>Community Ⅴ (0.5848)>Community Ⅰ (0.5775)>Community Ⅳ(0.5451)>CommunityⅥ(0.4551)>Community Ⅱ (0.3878)>Community Ⅲ (0.3684)。...