Comparison of Community Characteristics of Plantation and Secondary Forest of Pinus armandii in Huoditang Forest Region of Qinling Mountain

The community characteristics of the Pinus armandii plantation and the secondary forest were comparatively studied by standard quadrat method in Huoditang Forest Region.The results were shown as follows:(1)Secondary forest consisted of 82 vascular species in 38 families and 64 genera,whereas the plantation included 71vascular species in 30 families and 55 genera.A similarity index of 0.55 was obtained with 70 co-occurring species.(2)The maglef index,simpson index,Shanon-Wiener index and pielou evenness index of shrub and herb were not significant difference between the plantation and secondary forest.Which in arbor layer of plantation were significant lower than that of secondary forest.In the plantation,the four diversity indexes were in the order shrub layerherb layerarbor layer,which in secondary forest were in the order shrub layerarbor layerherb layer.(3)In life form spectrum,phanerophyte,chamaephyte,hemicryptophyte,geocryptophyte and therophyte were not significant difference between the plantation and secondary forest,but mesophanerophyte and microphanerophyte of secondary forest were significant higher than that of the Plantation by contrast of nanophanerophyte.(4)In the vertical structure,tree species composes in the arbor layer and number of generation in the shrub layer of secondary forest were richer than that of plantation.Mean height of Pinus armandii and cover of arbor layer,shrub layer and herb layer were not significant difference between plantation and secondary forest.(5)In the horizontal structure,the spatial pattern distribution of Pinus armandii population in the plantation was uniformly distributed,which was aggregate distribution in secondary forest.In the secondary forest,Pinus armandii was different aged population mixed with Tsuga chinensis,Tilia chinensis,Quercus aliena var.acuteserrata and so on.While in the plantation,DBH class of Pinus armandii was uniform and tree species were simple.(6)The compose index of secondary forest community was 3.20,higher than that of plantation of 1.49.The ratio of the climax tree in the secondary forest was 34.7%,higher than that of plantation of 22.7%,which indicated that secondary forest was on the late stage of the pioneer community,while plantation was on the early stage of the pioneer community.After 40 a recovery,two communities had high similarity and their distinction was in the arbor layer and succession stage.The tree species of secondary forest were richer in the arbor layer and succession speed was faster than that of plantation.