Interspecific And Intraspecific Relationship Of Pinus Fenzeliana Communities

Pinus fenzeliana(Pinaceae)is an endemic species to China.It is also an endangered species which is in "List of Wild Plants of National Key Protection" as the second class protected plant.The type of species be investigated in Hainan.In order to verify the interspecific and intraspecific relationship of P.fenzeliana communities in Hainan,we carried out a series of the typical sampling investigations based on the field survey.We calculated and summarized the date and based on the 2 X 2 contingency table,a series of approaches including variance ratio(VR),χ2-test,Pearson’s correlation,Spearman’s rank correlation,coupling index(AC),Jaccard coefficient(JI)and point correlation coefficient(PCC)were adopted to analyze the interspecific association among the vertical layers in P.fenzeliana communities and the association between P.fenzeliana and various layers of species.Using single tree competition model of Hegyi analyze the interspecific and intraspecific competition relationship of P.fenzeliana communities in Hainan.At the same time,according to the environmental factors information,we analyzed the relationship between interspecific competition of P.fenzeliana and enwironmental factors.The results showed that:On the vertical layers in P.fenzeliana communities,the dominant species were significantly positive correlated which indicated a relatively stable succession status of the current communities.There was an obvious positive correlation between with the species pair of the tree layer and shrub layer,the herb layer had a little negative correlation.The coupling degree between P.fenzeliana and the each species of the vertical layer were not significant,mostly of each were negative tendency of connection.In the community,the intraspecific competition intensities of P.fenzeliana is 171.63,the interspecific competition intensities is 560.18,indicating a remarkable effect of interspecific competition.By discussion the relationship between the diameter at breast height(DBH)of P.fenzeliana and intensity of competition,the regession results show that the power function model(CI=aDb)is the optimal model.With the DBH of P.fenzeliana increasing,the intensity of competition is reducing,when the DBH reaches 35cm,the intensity of competition tends to be stable.In summary,in order to ensure P.fenzeliana grow better,the companion which strongly influence P.fenzeliana(such as Castanopsis hainanensis,Symplocos heishanensis)should be pruning or thinning before DBH of P.fenzeliana reached 35cm.At the same time,the number of negative association species should be controlled,like Memecylon ligustrifolium,Ficus variolosa.Combined the environmental factors,small P.fenzeliana can be planted where the environmental factors are fit for them growing,such as altitude between 750m～950m,and so on.