The Predicting Models Of Crown Volume And Crown Surface Area About Main Species Of Tree Of Beijing

Urban forest ecological functions seem more important due to the issue of Beijing urban environmental deterioration, tree crown is an important part of forest ecosystem has become an important research topic now, this paper gets the point cloud data of sample tree by using three-dimension terrestrial laser scanning technology and study the establishment of the power function of the crown surface area, volume predicting models,in order to accurately and efficiently acquire crown surface area, volume. This paper takes the main tree species of urban six districts of Beijing as the research object including Bungeana, Indus, Tabulaeformis, Sabina, Ginkgo, Arborvitae, Cedar, Willow,Sophora japonica, Ailanthus, and uses terrestrial 3D laser scanner FARO LS880 to scan three-dimensional contours of sample trees. Secondly, extract the point cloud of crown section by using Faro Scene according to the coordinates of the point cloud of sample trees, exclude unconnected items, outliers and other processing of data with Geomagic studio12 3D reverse software. Eventually, accurately extract the maximum crown diameter(D), crown height(h) and other tree measurement factors. And according to the convex hull calculation principle—QuickHull to calculate the outer convex hull of crown point cloud, and calculate tree crown surface area, volume according to the obtained convex hull based on the MATLAB platform. Analysis of the correlation of crown surface area(S), volume(V) and maximum crown diameter(D), crown height(h) by using the corrcoef function to determine the best tree measurement factors involved in the establishment of model. Using the curve fitting tool toolbox to establish the crown surface area, volume predicting models of the ten main tree species of urban six districts of Beijing based on the power function to accurate estimation, crown surface area,volume of similar stand. Finally, on the basis of the good fitting results of the crown surface area, volume predicting models to evaluate the predicting models, and according to the statistical tool vartest2 function to test the effectiveness of the predictions of crown surface area, volume predicting models, and prove that the model is enough to meet the requirements of predicting the crown surface area and volume of the main tree species of urban six districts of Beijing in this paper.