三尖杉所属群落优势乔木树种种间关系

采用样方调查法,对组成大岗山三尖杉所属群落的乔木树种进行调查.通过计算重要值确定三尖杉所属群落优势乔木树种,在此基础上,研究优势树种的总体联结性、两树种间的联结性和种间协变.结果表明:三尖杉所属群落内的15个优势乔木树种总体间存在显著正关联;两树种间具有显著正联结的种对是细枝柃-梾木、红楠-杉木,呈显著负联结的种对是石栎-杉木;三尖杉与其他优势乔木树种的联结性均未达到显著程度,细枝柃-鹿角杜鹃、细枝柃-梾木、细枝柃-三尖杉、梾木-紫楠、红楠-杉木、红楠-拟赤杨等6个种对表现出明显的正协变,鹿角杜鹃-柃木种对表现出明显的负协变;种对正协变的存在是由于这些物种对环境资源的利用具有相似性所致.

Interspec ies Connection of Dom inant Tree Spec ies inCepha lotaxus fortune i Commun ities

Based on the samp le p lot investigation method, the tree species of Cephalotaxus fortunei community wereinvestigated in DagangshanMountain, The main tree species of Cephalotaxus fortunei communitywere ascertained bycomputing the Importance Value of tree species. The overall association of the dominant tree species , theinterspecific association of dominant tree species and interspecific covariation of the dominant tree species werestudied. The result showed that the overall association of the dominant tree species was positive. The pairs ofpositive interspecific association were as following: Eu rya loquaiana2Cornus m acrophylla, M ach ilus thunbergiiCunningham ia lanceolata; The interspecific association ofL ithoca rpus glabra-Cunn ingham ia lanceola ta was negative.The interspecific associations of Cephalotaxus fortunei with other specieswere not significant. There were 7 pairs ofspecies showing a significant interspecific covariation, 6 pairs were positive interspecific covariation, They were:Eurya loquaiana-Rhododendron latoucheae, Eu rya loquaiana-Cornus m acrophylla, Eurya loquaiana-Cepha lotaxusfortunei, Cornus m acrophylla-Phoebe sheareri, Mach ilus thunbergii-Cunningham ia lanceolata, and M achilusthunbergii-A lniphyllum fortunei. Only the interspecific covariation of Rhododendron la toucheae with Eu rya japon icawas negative. The reason for positive interspecific covariation was that these species used the resource similarly.