Research By The Stand Density Effect On Xing’an Larch Of Natural Forest

This research takes the different stand density (1700,2400,3200,4000strains of hm-2) determination of physicochemical properties, Xing’an Larch middle age forest soil under forest vegetation diversity and biomass of different density in Xing’an larch forest, soil organic matter, N\P\K content and vegetation diversity refers to the number and distribution of carbon density and the relationship between them, revealing the Xingan larch forest stand density on soil physical and chemical properties, carbon density and understory vegetation diversity of regulatory mechanism. The main results are as follows:Xing’an Larch forest soil pH value with the increasing of stand density increasing regularity, the values are:5.29,5.50,6.88,5.97; the content of organic matter are:46.29g/kg,68.26g/kg.72.33g/kg.46.71g/kg; nitrogen content respectively:2.80%,4.24%,4.46%,3.30%;phosphorus content in soil layer respectively:0.28%,0.48%,0.53%,0.40%; potassium content in the soil layer is respectively:16%,16.99%.17.32%,14.72%.Xing’an Larch middle age forest in different stand density aboveground total biomass respectively:76.94t·hm-2、94.02t·hm-2、99.42t·hm-2、88.93t·hm-2; the tree layer biomass are:54.37t·hm-2、69.13t·hm-2、68.70t·hm-2、60.62t·hm-2; shrub biomass size order wood:2.47t·hm-2、1.90t·hm-2、1.60t·hm-2、1.41t·hm-2:herbaceous biomass in order of size:2.03t·hm-2、1.46t·hm-2、1.12t·hm-2、0.79t·hm-2; numerical layer biomass of litter:18.07t·hm-2、21.53t·hm-2、28.00t·hm-2、26.11t·hm-2.Xing’an Larch middle age forest in different density underground portion of the total carbon density size:38.77t·hm-2、47.53t·hm-2、50.00t·hm-2、44.71t·hm-2; the tree layer carbon density are:27.85t·hm-2、35.47t·hm-2、35.11t·hm-2、30.99t·hm-2. Carbon density size is of the order of shrubs as:1.19t·hm-2、0.92t·hm-2、0.77t·hm-2、0.68t·hm-2; herb carbon density in the order:0.92t·hm-2、0.66t·hm-2、0.51t·hm-2、0.36t·hm-2. Litter layer of carbon density size:8.82t·hm-2、10.51t·hm-2、13.67t·hm-2、12.75t·hm-2.A total of9species of shrub layer, maximum species richness of shrub layer in the stand density was1700plants hm-2near. The biodiversity index, when the stand density was4000plants hm-2, diversity index is the highest. Xing’an Larch Forest in the shrub layer and blueberry, its important value in each stand density were higher than50%The species richness of herb layer is higher than shrub layer species richness, the size distribution and the same shrub layer distribution trend, are decreased with increasing of stand density. Distribution between the herb layer each species are more balanced, so the diversity index and evenness index of herb layer regularity is obvious, is decreased with increasing of stand density.4stand densities were found22species of herbaceous species. For the whole of the herb layer, the important value of each species are concentrated in0.01-0.05.