Dominant Species of Regeneration Niche in Quercus liaotungensis and Pinus tabulaeformis Forest in Ziwuling Mountain

Based on field survey to Ziwuling Mountain,the generational(seedling,sapling and adult) niche breadths of Quercus liaotungensis and Pinus tabulaeformis were studied with adopting Levins index in different community types,which was Q.liaotungensis forest,P.tabulaeformis+Q.liaotungensis mixed forest and artificial P.tabulaeformis forest on sunny and shady slope .The results showed that the generational niche breadths of Q.liaotungensis and P.tabulaeformis were different in these community types.The niche breadth of adult was the same as community.The niche breadths of Q.liaotungensis seedling and sapling were the highest in artificial P.tabulaeformis forest on sunny slope and shady slope,which were 0.951,0.95,0.98 and 0.94.There were significant differences among other communities.It indicated the growth of Q.liaotungensis seedling and sapling was inclined to the environmental condition of artificial P.tabulaeformis forest.The niche breadth of Q.liaotungensis seedling was the highest in Q.liaotungensis forest on sunny slope and artificial P.tabulaeformis forest on shady slope,which were 0.79 and 0.63.There were significant differences among other communities.The niche breadth of Q.liaotungensis sapling was the highest in artificial P.tabulaeformis forest on suuny slope and in P.tabulaeformis+Q.liaotungensis mixed forest on shady slope,which were 1.00 and 0.83.There were significant differences among other communities.The growth of P.tabulaeformis seedling was adaptable not only to the environment condition of Q.liaotungensis forest on sunny slope,but also to that of artificial P.tabulaeformis forest on shady slope.The growth of P.tabulaeformis sapling was adaptable not only to the environment condition of artificial P.tabulaeformis forest,but also to that of Q.liaotungensis forest on sunny slope.As a whole,artificial P.tabulaeformis forest had an important effect on the restoration of natural vegetation in this region.Artificial P.tabulaeformis forest and P.tabulaeformis+Q.liaotungensis mixed forest would have existed over a long period of time,while P.tabulaeformis+Q.liaotungensis mixed forest on sunny slope would have even more.