Study On Niche Characteristic And Succession Of Dominant Trees In Conifer And Broadleaf Mixed Forest In Qingshan Lake

Natural forests in Zhejiang Province play an important role in regulating climate, conserving water, soil and water conservation, conservation of biological diversity, maintaining ecological balance, with the plantation forests can not match, and is the no substitute renewable resources. But long-term destructive using of natural forests causes it depleted, how effective rehabilitation and construction of natural forests is imminent. According to the conifer and broadleaf mixed forest simple plots inventory data in Qing'shan Lake, the artical quantitative analysis of secondary succession, niche characteristics and the law of dynamic evolution.Based on the interspecific association, main component analysis, division method of Fisher optimization, and Markov succession model, the secondary succession of conifer and broadleaf mixed forest on the natural condition in the mountainous county, Qing'shan Lake, Zhejiang Province was quantitative analyzed. The results showed that①during the natural recovery process, 6 tree species such as Pinus massoniana, Cunninghamia lanceolata were declined, 14 species such as Camellia fraterna Hance, Schima superba, hoerospondias axillaries were transient species, 4 species such as Castanopsis sclerophylla, Cyclobalanopsis glauca were progressive species.②the succession process was divided into four stages : stage 1, the conifer and broadleaf mixed forest dominated by Pinus massaniana, Castanopsis sclerophylla, Ilex pubescens; stage 2, the conifer and broadleaf mixed forest dominated by Pinus massaniana, Cyclobalanopsis glauca, Castanopsis sclerophylla; stage 3, conifer and broadleaf mixed forest dominated by Cyclobalanopsis glauca, Castanopsis sclerophylla, Pinus massaniana; stage 4, broadleaf forest dominated by Cyclobalanopsis glauca and Castanopsis sclerophylla.③the secondary succession was predicted by markov model that about 20 years were essential for every stage, and 80—100 years later the succession will be over.Four common formulas were calculated for the twenty-four populations taking comprehensive community grandient as resources axes. The ecological suggestions of results were analyzed to reveal the effects for population to utilize resources and the capacity for population to adapt to environment. Results showed that:①The majority species such as Pinus massaniana, Castanopsis sclerophylla, Cyclobalanopsis glauca were wide niche.②All the dominant populations, both shade tolerant and intolerant, showed some adaptation to the community environment.③The niche overlap and exploitation competition had some correlativity, but they were not equivalent. The utilization spectrum of dominate populations in vertical space was complementary, but they had higher interspecies niche overlap value and extensive competition.Markov Model forecast the law of niche characteristics evolution of conifer and broadleaf mixed forest of Qing'shan Lake. Niche breadth of declined species continuously decreased, the niche breadth of the transient species first increases and then gradually decreases, and the niche breadth of progressive species is growing. The niche proportion simulation and the niche overlap of dominant trees have no obvious rule.