Quantitative characteristics of Pinus tabulaeformis and Quercus mongolica community in Dongling District of Shenyang,northeast China

The quantitative characteristics of community of Pinus tabulaeformis and Quercus mongolica distributed in Dongling District,northeast China's Shenyang City were investigated.The results show that there are 161 seed plants classified in to 49 families and 121 genera.A close relationship between this community and the temperate flora is approved because 143 seed plants,which occupy 88.82 % of the total,belong to the temperate biome.With regards to the structural feature of the community,hemicryptophyte occupies 36.02 % of the total and dominates the community,and its vertical structure is composed of three layers:arbor layer,shrub layer and herb layer.Niche breadths and overlaps of 10 woody plant species were calculated by the Equations of Ievins niche breadth and MacArthus niche overlap. The results indicate that Ulmus pumila,Crataegus pinnatifida,P.tabulaeformis and Euonymus alatus have high niche breadth,which are 0.519 3,0.491 6,0.481 7 and 0.459 4 respectively,and P.tabulaeformis shows its importance by a higher niche breadth value and the highest niche overlap value.On the contrary,Prunus padus has the lowest niche overlap and usually acts as dominant species in some special microhabitats.Only Crataegus pinnatifida and Phellodendro amurense show a significantly positive interspecific relationship,while other pairs of species have a highly negative interspecific relationship.