Variation Laws of Interspecific Relations of Michelia macclurei and Pinus massoniana Mixed Forest in the Coastal Upland of South Fujian

The research on variation laws of interspecific relations of Michelia macclurei and Pinus massoniana in the coastal upland of South Fujian indicates that: the mixed forest takes up individual nutrition spaces and doesn't cause interspecific competition during the lst-3th years, during the 4th-5th years. the stand, which begins colsing, forms more harmonized interspecific relations and keeps its relative stabilization, full shows its auxiliary function of the associated tree species, obviously improves its microclimate, and accelerates its growing speed; during the 6th-10th years, the interspcific competition, which is initial isn't intense, but the intraspecific competition of its associated tree species is principal; after the 10th year, the interspcific competition is gradually intense and gets to the competition peak,M.macclurei grows faster than P. massoniana whose growth is obviously restrained and dies down because of its wither; finally, the competition relations of the communities tend to ameliorate with the self-adjustment between the species. Based on the variation characteristics in the interspecific relations of the mixed forest, suitable thinning measures in plantation managements should be taken in time to adjust the interspecific relations of the mixed forest so as to bring the multi-benefits of the mixed forest into full play.