Study On The Spatial Structure And Plant Diversity Of Natural Broad-leaved Mixed Forest In Tongling Yeshan

This paper mainly disscusses the spatial structure, plant diversity, interspecificassociation and the diversity between spatial structure and plant by taking two types ofsecondary broad-leaved forest (type I and type II) in Tongling Yeshan timberland as theresearch object, through investigation, a typical plots that can represent the terrainconditions, community physical characteristics and species composition as sample hasbeen chosen to set tree quadrats. Five shrub layer quadrat of5m×5m with DiagonalMethods has been set up. and in which a1m×1m herb layer quadrat has been divided atthe diagonal cross A Survey including tree species, tree height, diameter at breast heightwithin the tree quadrats, and species name, numbers, cover degree, height and elevation,slope aspect, slope position, soil within shrub layer and herb layer, three-dimensionalcoordinates (X, Y, Z) in tree quadrats that can be measured with total station has been made,in which: x, y was the plane rectangular coordinates, z was the altitude. The buffer zone ofquadrats is5m, the start line for measuring diameter at breast height of trees is5cm.The research used the three parameters of diversity indices, evenness and ecologicaldominance in A diversity index for plant diversity, the stand spatial structure used the threeparameters of mixed degree, size ratio, interspecific association used the inspection of thechi-square combined with the correlation coefficient, Pearson correlation coefficient andSpearman’s rank correlation coefficient, the spatial structure parameters and plant diversitymodeling used the linear regression method.Two types of plants has similar composition, species richness within community, Inthe layer of type I, tree layer takes Fagaceae species as the dominant species, shrub layertakes Rosaceae species as the dominant species,the herbaceous layer takes fern as thedominant species: in the layer of type II, Gramineae and Liliaceae as the dominant species,the characteristics of forest community update significantly. Forest types I, the abundanceindex: shrub layer> tree layer> herb layer, diversity index: shrub layer> tree layer> herblayer, evenness index: shrub layer> tree layer> herb layer, ecological dominance: herballayer> tree layer> shrub layer. Forest types II, the richness index: shrub layer> herb layer>tree layer, diversity index: shrub layer> tree layer> herb layer, evenness index: shrublayer> tree layer> herb layer, ecological dominance: shrubs layer> herb layer> tree layer.In two types of plants, biological diversity index and dominance index showed a highlysignificant positive correlation, and negatively correlattion with uniformity. Type I has a total of190correlation log, chi-square test:66pairs of positivecorrelation,124pairs of negative correlation, Pearson correlation coefficient test:66pairsof positive correlation,124pairs of negative correlation, Spearman rank correlationcoefficient test:69pairs of positive correlation,121pairs of negative correlation. Type IIhas171correlation log, chi-square test:58pairs of positive correlation,113pairs ofnegative correlation, Pearson correlation coefficient test:54pairs of positive correlation,117pairs of negative correlation, Spearman rank correlation coefficient test:54pairs ofpositive correlation,117pairs of negative correlation, It shows the three test methodsconsistent.About forest spatial distribution pattern, stand average angular scales: type II (0.56)>type I (0.51), belonged to the same random distribution, the distribution frequency ofangular scale value complies with normal distribution, community is in well developmentand protection. On the degree of competition, the average of size ratio: type II (0.50) type>I (0.49), closed to the intermediate state (0.50), the degree of competition within thecommunity is low. The frequency of size ratio values changed from the state of advantagesto the absolutely bad state, the two communities showed a decreasing trend, the dominantspecies showed outstanding function in community establishment. The degree of spatialisolation, stand average maxed degree: type II (0.54)> type I (0.35), frequency of mixeddegree of type I valued from zero to the very intensive mixture and showed a decreasingtrend of community stability. Type II presented the low at the middle part and high at theboth edges, intensity mixture gradually reduced, and transited into the weak degree mixturetrend step by step, type II is the forest types in the transition successional stages, and thedegree of succession in type I is higher than that of type II. The relevance of angle scalesand mixed degrees showed a significant positive correlation, the size ratio has poorcorrelations with both of them.The model of Stand spatial structure parameters and biological diversity parametersare in line with the linear regression conditions, the correlation coefficient is relatively high,the adjusted correlation coefficient squared value is high, the error is small duringestimation, the significant level is low, the regression equation is significant with morethan90%accuracy.