Structure And Biomass Of Dominant Tree Of Natural Secondary Broad-leaved Forest In The Low Mountain Of Southern Anhui

Stand structures include spatial and non-spatial structure. Traditional forestry research contents are the space structures of the forest such as the tree species composition, age structure, diameter structure, tree heigh structure, density and volume etc. of stand, which are indispensable to description of the quantitative characteristics of a stand. They can show the information of characterstics and productivity of stand, but due to lack of space distribution information, and can’t make the correct judgment to selecting of management measures and techniques in forest management. With the rise of close to natural forest management, forest structures, process and many relationships and other detailed information, have become a more and more the premise of forest management. Stand spatial structure characteristics involving spatial relationship of trees are paid more and more attention, which have been becoming the main research contents of international natural fo management simulation technology.Four types of the natural secondary broad-leaved forests enclosed in1950’s were used as research object in Tonling and Qingyang county of Anhui Province in this paper. We choosed the typical area that can refled the characteristics of the forest type, and set survey sample plot. The tree with DBH>5cm in tree Iyer were surveyed and recorded their species, DBH, height, etc.. At the same time, the three-dimensional coordinates (X, Y, X) of all the trees in plot were measured for mapping the tree spatial position. To avoid edge errors, a5m suffer zone in which all the trees noted as neighbor wood was set around every plot. The plant species, number, coverage etc. of shurbs and herb layer were surveyed and recorded respectively. Mean standard wood of diameter class were selected to estimate the aboveground biomass of tree layer with a hierarchical method according to the dominant tree species. The aboveground biomass of shrubs and herb were estimated with full harvest method. Based on the field investigation, the plant diversity index and the spatial structure indices of each forest type were calculated. The models of aboveground biomass and growth of dominant tree species were built, and the aboveground biomass of stand were estimated. The characteristics of spatial and non-spatial structure of the different forest type were analyzed, which can provide the bases for plant diversity protection, stand spatial adjustment and optimization and biomass estimatiom.Type I is an deciduous and evergreen broad-leaved mixed forest dominated by Quercus acutissima and Cyclobalanopsis glauca, Castanopsis sclerophylla, etc. Type Ⅱ is a deciduous broad-leaved mixed forest dominated by Quercus acutissima and Platycarya strobilacea, Liquidambar formosana etc.. TypeⅢ is a deciduous broad-leaved mixed forest dominated by Quercus acutissima and Quercus chenii, Liquidambar formosana. TypeⅣ is a Quercus acutissima deciduous broad-leaved mixed forest. The dominated tree species are Quercus acutissima for the four forest types. The diameter disturibution for the four forest types showed the typical feature as even-aged stand.Type Ⅰ is Quercus acutissima and Cyclobalanopsis glauca-Deulzia glauca-Dryopteris peninsulae community, with a total of52plant species in33families and43genera. There are20species in13families and18genera in the tree layer,37species in22families and31genera in the shrub layer, and9species in8families and8genera in the herb layer. TypeⅡ is Ouercus acutissima and Platycarya strobilacea, Liquidambar formosana-Cyperus alternifolius-Phaenosperma globosa community with19plant species in12families and17genera in the tree layer. There are51plant species in31families and43genera in the shurbs layer, and23plant species in18families and23genera in the hurb layer, TypeⅢ is Quercus acutissima-Phyllostachys glauca-Liriope graminifolia community with3plant species in2families and2genera in the tree layer. A total of21plant species in17families and18genera occurred in the shrub layer and13palnt species in10families and12genera in the herb layer. TypeⅣ is Quercus acutissima-Phyllostachys glauca-Liriope graminifolia community. Tree species composition is from Quercus of Fagaceac and Zelkova of Ulmaceae. The dominant tree species is Quercus acutissima. Associated tree species are Zelkova serrata and Ouercus fabric. Surb layer has21plant species in17families and17genera. The herb layer has8plant species in7families and8genera.The Shannon-Wiener diversity indices were between0.18and1.25in the tree layers, between1.55and1.92in the shrub layers, and between0.24-1.43in the herb layers for the four forest types. Mean Shannon-wiener diversity index ranked as order of shrubs layer (1.67)>tree layer (0.85)> herb layer (0.74)In general, the stands of Type Ⅱ and TypeⅢ exhibited moderate mingling, but the stands of Type Ⅰ and Type Ⅱ exhibited weak mingling. The dominant species, Ouercus acutissima, exhibited weak mingling, associated tree species were moderate mingling for the four forest types. Stand average Neighborhood Comparison index was ranked as TypeⅣ (0.52)>Type Ⅱ (0.50)>Type Ⅰ (0.49)>TypeⅢ(0.47). Mean Neighborhood Comparison index of the dominant tree species was small than the associated tree species. Average Uniform angle index of stand was ranked as Type Ⅱ(0.56)>Type Ⅰ、TypeⅣ(0.51)>TypeⅢ(0.49). The dominant tree species of stands were all random distribution.The minimum sampling area of the spatial and not-spatial structure of the community is3600-3700m2for natural secondary broad-leaved forest in low mountain of southern Anhui. This sampling area can fully reflect the diversity of spatial and not-spatial structure, meet the need of precision of stand structure diversity research. Meanwhile, it can reduce work of field investigation and improve work efficiency.The above-ground biomass models for Ouercus Aculissima were:Trunk W=0.0197D2.1454H0.917.Branchs W=0.0959D3.2301H-1.279Leaves W=0.03214D1.7386H-0.518Total W=0.0397D2.3628H0.518.The model fitting effect of the total above-ground biomass was the best. followed by the trunk, branches and leavesLeaf area index of individual Quercus Aculissima was between0.55and4.01. Average leaf area index was about1.58. Leaf area ratio (dry leaf weight) was little difference, between5.37and8.26m2/kg. Leaf area model of individual tree was W=0.0310(D2H)0.7570.Total above-ground biomass of tree layer was between137.17t/hm2and180.34t/hm2. The order of the four forest types ranked as Type Ⅳ>TypeⅢ> Type Ⅰ> Type Ⅱ. Above-ground biomass of shurb layer was between8.78t/hm2and16.29t/hm2for four forest types.Total above-ground biomass of stand was between149.55t/hm2and195.11t/hm2. with an order as TypeⅣ>TypeⅢ> TypeⅠ>Type Ⅱ for four forest types. The order of the total above-ground biomass for the different layers was ranked as tree layer> shurb layer>herb layer. The above-ground biomass of the tree layer contributed more than90.0%of the stand total. The shrub and herb layers covered5.0%and0.1%of the stand total respectively.