Research On Stand Structure Of The Pine-Oak Mixed Forest In Huoditang Region Of Qinling Mountains

The forest structure was the foundation of ecological function,and was very important for forest health evaluation and management. We performed field experiments in Huoditang forest region located in southern slope of Qinling Mountains,and investigated a total of22pine-oak mixed forest study plot in order to systematic analysis the distribution regularity of trees diameter and trees height in forests. Besides,we also analysis the spatial structure characteristics in pine-oak mixed forest by spatial structure parameters including mingling,the diameter neighborhood comparision,and the neighborhood pattern.The results indicated as follows:(1) DBH class distribution in pine-oak mixed forest shows the inverse J distribution,on the height distribution,the number of trees among the most and gradually reduce to both ends. Spss regression shows that,the regression equation is:Y=-0.018x3-0.293x2+24.091x-90.568,R2=78.7%.The regression accuracy is high enough.(2) Divided the pine-oak mixed forest layer into less than10m,10m-16m and greater than16m according to trees height,results indicated that the number of the upper trees was the most and the lower trees was the least.(3) Dominant tree species was Quercus aliena var. acuteserrata.population of Quercus aliena var. acuteserrata and Pinus tabulaeformis population were the dominant population in pine-oak mixed forest.(4) Tree species segregation analysis in pine-oak mixed forest showed that:The percentage of pine-oak mixed forest plog which are in low mingling degree accounted for18.2%, and the percentage of the moderate,intensity,and high intensity forest were accounted for81.8%of the total. The results showed that the degree of segregation in pine-oak mixed forest is high,and the stability of the stand was strong.(5) Use angle index to analyse the pine-oke mixed forest’s spatial distribution pattern,the results showed that:clumped distribution stand in pine-oak mixed forest were accounted for82%,and the angle index’average maximum was not more than0.6397,belonged to mild clumped distribution,14%stands are randomly distributed in pine-oak mixed forest,it can be inferred that pine-oak mixed forest are in the medium-term community succession stage in Huoditang forest areas. In addition,relying on the stand visualization system (SVS) platform in Landscape Management System package of software tools,take the1st plog for example, visualization simulation cutting based on the basic principles of selecting harvesting wood,and analysis the forest spatial structure after simulation cutting,the results show that the trees after harvesting tend to random distribution,stand mingling degree increased,the average dominance degree was improved and harvesting effect was good,these results had theoretical and practical significance for health management in pine-oak mixed forest.