Research Of Larch Plantation Pruning

The data of field survey in this paper involved95sample trees of different densities and different site conditions in19plots at the Mengjiagang forest in Jiamusi city, Heilongjiang province researched in2007and2008. According to the anatomical analysis of trees, The growth process and size and its variation of the tree knot reflected by the data of anatomical analysis and disk to the larch plantation,can help us to determine the height of the tree and height below the canopy branches and the effective canopy height of trees and stands in the past time.In this passage, according to the established forecasting model of the tree height,height below the canopy branches and the effective canopy height of trees and stands,we can analysis the tree pruning program,in order to cultivate high-quality timber without knot of the larch plantation,the effect of the section able to increase the volume of wood and wood quality,and increase the volume of wood and wood quality.The article analysis larch plantation by Scatter plot of the tree height,height below the canopy branches and the effective canopy height of trees and stands with the data of disk and knot, the distribution showed exponent. With disc prediction model of tree height is constructed and analyzed, and the prediction model of the height below the canopy branches and effective crown height is established and analysised with the data of knot.The articles taking into account of the effect of the difference between the plots and sample trees, introduced in the mixed model based on the convergence model, analysis the difference between knot and sample trees,and the difference between plot and knot with mixed model.Nonlinear mixed models of tree height is established by disk height and the forest age of this height; with the relationship between the height of knot and the age at death time of branches,nonlinear mixed model of height below the canopy branches is established; The final analysis of the correlation of the height of knot and the age when branches growth stop, nonlinear mixed model of effective crown is established. The nonlinear Mixed Models use the fitting statistic AIC, BIC, log likelihood value and LRT evaluation index to compare the constructed model.The results showed that:when we consider the random parameters,the fitting effect of growth model is better than that basic model; In considering the effect of the sample trees, the fitting effect of the model of tree height growth is better than that when considering the effect of the plots. For the model of tree height growth, the fitting results are the best when the model with β1,β2as a random parameter;For the model of height below the canopy branches,the best fitting results are when the model with β1,β3as a random parameter; And for the model of effective canopy height, the fitting results are the best when the model with β1, β2as a random paramete.According to the established forecasting model of the tree height,height below the canopy branches and the effective canopy height of trees and stands,pruning intensity and periodicity program of the Larch plantation stand is established. In the canopyed stand,start the first artificial pruning at the age of11,pruning intensity strength from small to big and Last flatten.