The Study Of Taper Equation For Larix Olgensis Plantation

Base on the data of 95 trees and 208 actual cross-cutting sample trees from the plantation of Larix olgensis Plantation in different ages and densities and soil conditions in Mengjiagang Forest Farm in Jiamusi City, five Taper equations were made with parameter estimation method for non-linear regression model using the data of the relative stem form of each standard tree, and the equation effect and estimation accuracy of each model were analyzed and compared. The best taper equation of Larix olgensis plantation was selected to make a comprehensive evaluation towards the forecasting performance of the best taper equation. The volume table of Larix olgensis plantation was drawn with the best taper equation, which can provide theoretical base for production and practice. Results showed:(1)The regression model between the inside diameters and outside diameters in different parts of trunk can forecast the inside diameters at each relative height of each sample tree.(2)Base on analysis, comparison and evaluation of each model, the improved Lee(2003) Model is not only flexible and easy to draw up, but also has a very high estimating accuracy. It can estimate the inside diameter in any part and timber length with any small diameter of trees of different size for each tree species.(3) The same time, calculating statists of trunk section, indicators to identify different parts of the trunk for the stem curve to better recognition of shapes in different parts of the trunk, estimated the volume accurately.(4) The influence of forest stand density on stem form is large and the stem form quality of the forest stand with a low density is poor. The analysis of several stem form indexes indicates that these indexes can describe the variation of stem form very well. Although the growth of the forest stand with a low density is large, the stem form is poor which cause the declination of timber quality.(5) By using the best taper Equation peeled larch adaptive volume table F test results showed that the volume was not significant, the practical application of error is small, highly precision, showing that the volume table is applied to this area.