Study On Distribution Characteristics Of Chinese Fir In Subtropical Evergreen Broadleaved Forest

Chinese fir(Cunninghamia lanceolata)has a long history of cultivation which is the most important timber tree in southern China.Long time successive rotation of Chinese fir plantation in the same site cause the greatly decline of soil fertility and species diversity,and that become the important issue need solve quickly in forestry production.For the aim to solve the problem on management,we must know distribution characteristics of Chinese fir in natural succession evergreen broadleaved,and it has a great guiding significance for the close-to-nature forest management of Chinese fir.The current research about Chinese fir were most on plantation,but research on distribution of Chinese fir in subtropical evergreen broadleaved is relatively few,so it is necessary to study the distribution characteristics of Chinese fir in subtropical evergreen broadleaved forest.In view of this,this thesis selected three different subtropical evergreen broadleaved forest without human effect where has Chinese fir that through a long time natural succession were Wanmulin,Wuyishan and Mangdangshan Nature Reserve,used successive sampling and line transects to made an investigation.Through the analysis of different ecological characteristics for Chinese fir population in community,it revealed the distribution of DBH and spatial distribution pattern of Chinese fir in subtropical evergreen broadleaved forest,studied the mortality and expectation of life on different DBH,and made a forecast for succession of Chinese fir population;through the analysis of different ecological characteristics for subtropical evergreen broadleaved forest where has Chinese fir,in this paper it studied the composition of the community,plant species diversity,importance value of main species and the characteristics of niche,summarized the overall association in the tree layer and spatial structure,and provide scientific evidence for study the distribution characteristics of Chinese fir in subtropical evergreen broadleaved forest.The main results are as follows:1.There is not have Chinese fir seedling in Wanmulin nature reserve of Fujian province,but the Chinese fir seedling update normal in Wuyishan and Mangdangshan;except update age class,the number of Chinese fir is less in other age classes,and the number of Chinese fir is reach the maximum in near middle age class.As the time goes on,the research predicted DBH line of Chinese fir population became more gentle in evergreen broadleaved forest,the population number move to larger age class.2.The mortality mainly increased with the increase of Chinese fir's DBH in evergreen broadleaved forest,but has the negative mortality;the expectation of life mainly decrease with the increase of DBH.The spatial distribution pattern of Chinese fir in evergreen broadleaved forest in Wanmulin is not significant clumped pattern,and it is shows near random pattern,the spatial distribution patterns of Chinese fir in Wuyishan and Mangdangshan are random pattern.3.The family,genus,species in shrub layer and tree layer mainly are more rich in the evergreen broadleaved forest community where has Chinese fir,and the degree of species diversity is more higher,but the family,genus,species in herbaceous layer and interlayer are less,the degree of species diversity is more lower.All species have not significant negative correlation among tree layer in Wanmulin,and main species have not significant positive correlation;both all species and main species have significant positive correlation in Wuyishan;all species have significant positive correlation in Mangdangshan,but main species have significant negative correlation.4.It is first or second that the importance value of Chinese fir in evergreen broadleaved forest tree layer,Chinese fir has a great proportion among the total importance value in tree layer;the niche breadth of Chinese fir is first or second in subtropical evergreen broadleaved forest tree layer,and most of the main species have a high niche overlap with Chinese fir.5.All Nature Reserve evergreen broadleaved forest community have a high mean Mingling,mean neighborhood comparison is near 0.50,all the tree showed clumped pattern in Wanmulin evergreen broadleaved forest,all the tree showed even distribution in Mangdangshan and Wuyishan;The succession degree of evergreen broadleaved forest community showed that Mangdangshan>Wanmulin>Wuyishan,3 Nature Reserve evergreen broadleaved forest community are all have a high succession degree.