Structure Characteristic Of Natural Quercus Broadleaved Mixed Forest Community In Yeshan Tongling

In this paper, the natural Quercus broadleaf mixed forest in Tongling Ye Mountainwas used for study．We set a plot of120m×150m in which stand was preservation, theforest appearance tidiness and representative stands．And then, divided the plot into20standards of30m×30m．3tree standards were set up from low to upper middle slopeposition, the aggregate was12．5shrub quadrates of5m×5m were set by diagonalrelationship in which quadrates, the total was60, investigating and recording the type,coverage, number and the mean height etc．One herb square of1m×1m was set in everyshrub quadrat,60in all, investigating and recording the type, coverage, number etc．Usingtotal station to measuring coordinates of every tree(DBH≥5cm) in each tree plot, and thendrawing the distribution of different tree species by south case7.0, calculating mingling,neighborhood comparison and uniform angle index by winkelmass1.0．Stand spatialstructure and species diversity of the natural Quercus broadleaf mixed forest in TonglingYe Mountain was analyzed by using species diversity index, such as Species richness,Shannon-wiener index, Pielou index, and such three spatial structure parameters asmingling, neighborhood comparison and uniform angle index etc．The minimal area wasestimated,when the structure of community was stable, by using type＆area curve andstand spatial structure parameters＆area curve．At last, analysis of interspecific associationamong common species forests were performed in this study by using Pearson correlationand Spearman rank related coefficient．The results showed that：(1)The flora is wealth; tree species experience a regular pattern．In this research,58species of36genera and24families vascular plants are recorded,including fern and gymnosperm each has1species of1genera and1families,55speciesof34genera and26families of angiosperm．The number of tree, shrub and herbs arerespectively：19species of15genera and12families,37species of33genera and22families and9species of8genera and8families, accounting for29.2%,56.9%and13.9%,respectively, of the total．Undergrowth is relatively rich, especially shrubs which has37species, however, herbs just has9species．In species distribution, concentrated distributionof Pinus massoniana in sample uphill, also both high altitudes．Quercus acutissima, whichis the dominant species, distributes across altitudinal gradients．But the number of Quercusacutissima increases as altitude increasing, intensively distributing in medium elevation, and then reduce in high elevation．So, Quercus acutissima is the dominant species in lowaltitude． Other species expect Cyclobalanopsis glauca are random distribution．(2) Stand diameter appears normal but slightly left structure distribution, showing thediameter of the same age for structural features．The diameter class of stands isconcentrated distribution between14cm and20cm with the number of low diameter classtrees more than big diameter class ones．The average age of stand is50years old byanalyzing12trees, however, the structure characteristics of diameter and the reflection ofstand growth phase with the analytical results is inconsistency．(3)In tree layer, the species which important value is greater than5are Quercusacutissima, Pinus massoniana, Cyclobalanopsis glauca, Castanopsis sclerophylla,Lithocarpus glabra．And Quercus acutissima is the dominant species because of itsobvious advantages, Pinus massoniana, Cyclobalanopsis glauca, Lithocarpus glabra aresubdominant．In the shrub layer, the species which important value is greater than5areJuniperus formosana, Cyclobalanopsis glauca, Litsea cubeba and Dalbergia hupeana．Thevalue of Juniperus formosana is the most,and the edificatory．In the herb layer (includingliana),the important value of Dryopteris peninsulae,Dryopteris erythrosora,Phaenosperma globosa,Ophiopogon Japonicus, Fiveleaf Gynostemma Herb are greaterthan5,the edificatory is Dryopteris peninsulae．(4) The species richness in three layers is shrub layer(37species)>treelayer(19species)>herb layer(9species)．Shannon-wiener index(H′) from high to low isshrub layer(1.575)>tree layer(0.941)>herb layer(0.244)，the index of Pielou(J) is shrublayer(0.747)>tree layer(0.557)>herb layer(0.288), but the Simpson(D) index is herblayer(0.559)>tree layer(0.531)>shrub layer (0.287)．Both Shannon-wiener index and Pielouindex are maximum in shrub layer, yet Shannon-wiener index in herb layer isminimum．The Simpson index of herb layer shows that this layer is under control byDryopteris peninsulae．However,it is lower in tree layer and shrub layer, it meansthat both layers are comprised of several edificatories and competitive．(5) On stand spatial distribution, the average uniform angle is0.510, appearing thenormal distribution,which means the stand distribution is random and shows thatdevelopment and protection of the natural Quercus broadleaf mixed forest is well.Theaverage mingling is between weak and moderate mingling, its value is0.345.This showsthat species gather, isolation is lesser among different species, and structural unit isrelatively single.The average mingling of Quercus acutissima is0.216, appearing singlespecie gathering.The average neighborhood comparisions is0.492, showing an unsignificant differentiation of the stand．But the difference is signicant in diameter of treesbecause of the average diameter neighborhood comparision of different species is0.310~0.938．The Pinus massoniana(U=0.310) has an advantage over others, suppressedand absolute suppressed species, which has a small percentage, are Lithocarpus glabra,Vernicia fordii, Mallotus japonicus and Litsea cubeba．(6) The results showed that the minimum sampling area of the not-spatial structure is3720m~2(a square with sides of61meters) by using species-area curves; and the minimumsampling area of the spatial structure was3600m~2(a square with sides of60meters) byusing the stand spatial structure parameters-area．(7)Observably and insignificant positive correlation of Pearson correlation are14and40respectively, but observably and insignificant negative correlation are4and113,irrelevant correlation is19．The result of Spearman rank related coefficient shows： Theirrelevant correlation is the same to Pearson correlation, observably and insignificantpositive correlation are11and58, observably and insignificant negative correlation are1and101．The ratio of significant and highly significant positive correlations is much lowerthan significant and highly significant negative correlations, On the whole, negativecorrelations is predominant．...