Analysis Of The Community Main Structure Change In Evergreen Broad Leaved Forest In Tianmu Mountian

The concept of forest ecosystem large and permanent quadrat is in the study of the structure and function,the inherent law and change mechanism of forest ecosystem system.It is widely used in academia and the promotion of scientific and effective method today.The National Nature Reserve of Mount Tianmu is a typical subtropical evergreen broad-leaved forest area on the southeastern coast of China,and subtropical evergreen broad-leaved forest is one of the main types of forest ecological system.Therefore,it's very meaningful to set up a large and permanent quadrat in a selected and typical subtropical evergreen broad-leaved forest in the National Nature Reserve of Mount Tianmu to locate long-term observation and research.In this paper,variety data processing and analysis of the data which are measured in 16 years time span between 1996 and 2012 in the selected and typical subtropical evergreen broad-leaved forest in the National Nature Reserve of Mount Tianmu,including niche breadth,coefficient of niche overlap,biodiversity,interspecific association and biomass.The main results are as follows:(1)The 12 dominant species which have the important value of 10%or more arrange as Cyclocarya paliurus?Cunninghamia lanceolata?Cyclobalanopsis myrsinifolia?Liquidambar acalycina?Daphniphyllum macropodum?Eurya hebeclados?Litsea auriculata?Cornus kousa subsp.chinensis?Cryptomeria fortunei?Lithocarpus harlandi?Catalpa ovata?Lindera erythrocarpa in 1996 and Cyclobalanopsis myrsinifolia?Cunninghamia lanceolata?Cyclocarya paliurus?Daphniphyllum macropodum?Lithocarpus harlandi?Liquidambar acalycina?Cornus kousa subsp.chinensis?Cryptomeria fortunei?Litsea auriculata?Eurya hebeclados?Nyssa sinensis?Cyclobalanopsis stewardiana in2012 according to the size of important value.(2)The Shannon-Weiner index,Pielou index and Simpson's index of the trees which are over 10cm DBH respectively are 4.126829,1.104118,0.908350 in 1996 and 4.022551,1.023075,0.899500 in 2012.(3)The niche breadth of Cyclocarya paliurus is the biggest among the dominant species in 1996,and the niche breadth of the other dominant species according to the order from big to small is:Cunninghamia lanceolata?Daphniphyllum macropodum?Cyclobalanopsis myrsinifolia?Liquidambar acalycina?Eurya hebeclados?Cornus kousa subsp.chinensis?Litsea auriculata?Lindera erythrocarpa?Cryptomeria fortunei?Catalpa ovata?Lithocarpus harlandii?The niche breadth of Quercus myrsinifolia is the biggest among the dominant species in 2012,and the niche breadth of the other dominant species according to the order from big to small is:Cunninghamia lanceolata?Cyclocarya paliurus?Daphniphyllum macropodum?Lithocarpus harlandii?Cornus kousa subsp.chinensis?Litsea auriculata?Eurya hebeclados?Cryptomeria fortunei?liquidambar acalycina?Nyssa sinensis?Cyclobalanopsis stewardiana.(4)The dominant species have different degree of niche overlap between except for Lithocarpus harlandii and Cornus kousa subsp.Chinensis?Lithocarpus harlandii and Lindera erythrocarpa in 1996 and all of the dominant species have different degree of niche overlap between in 2012.Besides,the rate of niche overlap in 2012 is higher than 1996.(5)The total biomass of each kind of macrophanerophytes(DBH?10cm)is 151.03t,and the average biomass is 151.03t/hm2 in 1996.The total biomass of each kind of macrophanerophytes(DBH>10cm)is 151.03t,and the average biomass is 151.03t/hm2 in 2012.A comprehensive analysis of the calculation results of every community indicators by time-scale is used to Analog the change situation,the change rule and the change trend of community composition and structure between 1996 and 2012.The results show that from 1996 to 2012,in this process of community evergreen broad-leaved forest succession,Quercus myrsinifolia and Lithocarpus harlandii have the most obvious advantage,Cyclobalanopsis stewardiana,Nyssa sinensis,Daphniphyllum macropodum,Cornus kousa subsp.Chinensis and Litsea auriculata also have some advantage.However,Lindera erythrocarpa,Catalpa ovata,Cryptomeria fortunei,Cunninghamia lanceolata,Eurya hebeclados and liquidambar acalycina don't have the advantage and Cyclocarya paliurus is in a position of being phased out.On the whole,these results consistent with the succession trends of the evergreen broad leaved forest in Mount Tianmu(From needle gradually transition to mixed broad-leaved forest,broad leaved tree species will replace conifer fortunei,etc as the main dominant species).It also can be used to provide reference and reference about the subtropical evergreen broad-leaved forest resources of forest succession forest ecological system.