Simulation of the Outer Profiles of Pinus koraiensis Crown Under Different Climatic Conditions Based on Dumb Variables

Abstact: This paper studied the Pinus koraiensis plantation of Dabiangou Forest Farm in Qingyuan Manchu Autonomous County, Liaoning Province and Mengjiagang Forest Farm in Huanan County, Heilongjiang Province, by selecting 39 and 24 sample trees in 2 climate areas for branch analysis. Measure the branch length, chord length, base diameter, branch depth of all branches, construct crown profile model of 2 P. koraiensis regions based on dumb variables using R language, analyzing the influence of forest factors on crown profiles, and compare the differences of crown contour of P. koraiensis in the 2 climatic regions. The results show that among the power function, the segmented parabola function and the modified Kozak equation, the power function had the best fitting effect of tree crown profile, the power function equation was chosen as the basic model of tree crown profile; when only one of the other factors changed, the crown radius increased with the increase of DBH and CL, and decreased with HD, and CR had the least effect on the crown radius, followed by HD and DBH was the largest. Regional differences affected small trees the most, followed by medium trees, and smallest large trees; dominant crown radius > intermediate crown radius > supressed crown radius. The dumb variable model of the outer crown profile constructed in this study has a goodness-of-fit and can reasonably simulate and predict the outer crown contour of red pine in 2 regions.