Stand Harvest Analysis And Information Management System For Target Tree

The goal of modern forest management is to cultivate a stable and healthy forest ecosystem.But theconventional forest management mode in which timber supply is the focus cannot achievethe goal.The sustainable multi-functional forest management provides a solution.that Close-to-nature forest management is an effective means to achieve this goal. Throughout the process of forest cultivation, the stand tending treatments under close-to-nature forest management primarily focus on the target tree. The best forest trees in terms of tree species, dominance degree, stem form, crown type and vitality were selected in order to maintain good performances. Stem form determines not only the quality of timber, but also that of the harvest. Generally, target trees are those with straight and plump stem form. Among the existing technologies, the stem form is only evaluated qualitatively. We proposed a method for quantitatively evaluating the stem form of target trees, and contributed for theestablishment of quantitative indicators of stem form.In this study, three precious tree species, namely, Castanopsis hystrix, Erythrophleum fordii and Tectona grandis, were chosen as the research subjects from the experimental center of tropical forest.. For each tree species, 10 temporary plots(totally 30 plots) were set up. One dominant tree, subdominant tree, normal tree and suppressed tree were selected in each plot, respectively. After felling, the stem form data were collected from 120 trees. The differences in stem form, bucking and harvest between target trees and ordinary trees were investigated. Using the data of sample plot survey by the "center" through dynamic monitoring, the calculation method for systematic plot sampling and data analysis were performed for the trees in the "center" and in the subfield to predict the values of the following indicators: stock volume, growth volume, difference in stock volume and growth volume between target trees and ordinary trees. Pinus massoniana, Cunninghamia lanceolata and Castanopsis hystrix were subject to systematic sampling based on three-parameter Weibull distribution expression. The differences in bucking and harvest between the target trees and the ordinary trees were analyzed. With the help of information technology and using the data from systematic sampling of the plots, we studied GIS-based data management of target trees. The research results were then applied to managment practice according to the current situation of management. The main achievements were as follows:1) Simple taper function, Segmented taper function and variable exponential function were used as the basic models of stem form for Castanopsis hystrix, Erythrophleum fordii and Tectona grandis, respectively. Piecewise taper function fitted by two-factor automatic and optimal selection algorithm had the highest precision and the best effect. Two-factor automatic and optimal selection algorithm was then used for the fitting for each type of trees for each species(dominant tree, subdominant tree, average tree and suppressed tree). The stem profile curves were obtained. Timber volume, chest-height form-factor, ordinary form factor, experimental form factor, form quotient and height-diameter ratio were analyzed for each species. The following results were found for Castanopsis hystrix, Erythrophleum fordii and Tectona grandis: tree height, diameter at breast height and timber volume of dominant trees were higher than those of average trees; chest-height form-factor, experimental form factor and height-diameter ratio of dominant trees were smaller than those of average trees. As to ordinary form factor, the dominant trees with 0-0.5H had a smaller increase rate of normal form factor than that of average trees; at 0.75 H, the increase rate of diameter at breast height of dominant trees was larger than that of average trees. As to form quotient, the dominant trees with 0.75 H had a smaller decrease rate of trunk diameter than that of average trees. The analysis of stem form model showed that at any height of tree, the absolute diameter of target trees was larger than that of ordinary tree. When the tree trunk was larger than 0.75-0.8, the rate of taper of target trees was larger than that of ordinary trees.2) Combining stem form model, database technology and programming technique, the computer-assisted automatic bucking tool was realized. Theoretical bucking was modeled for a single tree for each tree type. The results showed that the timber volume of dominant trees of Castanopsis hystrix, Erythrophleum fordii and Tectona grandis was far greater than that of ordinary tree, and sometimes the difference was as large as 2 times, or at least 1.4 times that of the ordinary tree. The outturn of dominant trees of each species was larger than that of average tree. Dominant trees mainly produced large-diameter timber and medium-diameter timber came the second. Average trees mainly produced small-diameter timber and medium-diameter timber came the second.3)Based on the systematic sampling survey data analysis, volume estimation results show that the target tree number into a small number, but the target tree volume accounted for greater than the number of average tree; and the average tree have a large percentage, but the volume is less than number percentage. The target tree management model can produce more volume than other management models.The result of biomass estimation show that the rate of target tree growth faster than the average tree. The growth increments of target tree of Masson pine pure forest,Chinese fir pure forest,conifer-boradleaves mixed forest were two times of those of tree individual number, and the growth increments of average tree were 0.8 times of average percentage.Different kinds of log bucking schemes were studied and their volume ratio and average price were compared. The results showed that there were significant difference in average price with different bucking schemes.The benfit of Masson Pine forest and Chineses fir from the closed to natural forest management obtained the highest merchantable average pricecompared by the traditional management. moreover, through comparatively analysis on the growth increments of target tree faster than ordinary forest management,the paper finally put forward that closed to natural forest management model is a rational choice and best bucking scheme.for China to develop fast-growing and high-yielding timber forests.4) The connotations and functions of data management of target trees were analyzed; the architecture of GIS-based data management system and the multi-layer data management mode were designed; scientific metadata of forest management were divided into 8 dimensions, namely, time dimension, data hierarchy dimension, affiliated project dimension, subject dimension, spatial position dimension, processing attribute dimension, storage medium dimension and data format dimension. Each dimension was coded. Pre-tree scaling data of plot based on systematic sampling were used for spatial location of single trees. Spatial data storage model was employed for unified storage management of spatial data and attribute data of single tree.5) To achieve the target tree GIS based data management instance, realize the corresponding function like individual tree data, plot data and resource data to implement land in the hills, is expected to result system based survey data, you can visually estimate any accumulation of small class harvesting, bucking harvesting and currency gains.The main contribution of the paper as follows :1) Two-factor automatic selection algorithm is proposed and realized in the segmented stem form curve fitting.it solves the problem that the estimated parameters of inflection point( the relative tree height with numerical region of 0 to 1) obtained by Ordinary Least Squares regression do not ensure to fall into the region of 0 to 1,the method could indicate the optimal value segmented taper equation parameters theoretically.2) Taking an example of precious species(Castanopsis hystrix、Erythrophleum fordii and Tectona grandis,it is the first time to distinguish the stem form、bucking and harvest difference between target tree and ordinary tree.it indicates taht the target tree management system can play a ecological benefits and access to high-value timber at the same time,The amount of the target tree timber, the timber harvest rate and currency are larger than the ordinary tree,the target tree produces a large-diameter timber and Middle-diameter timbermainly, but ordinary tree produces Middle-diameter timber and small-diameter timber mainly.3) The target tree data management system based GIS is constructed,which uses multi-level data management,his metadata management is divided into eight dimensions,it is realized that the unified management of spatial data and attribute data for The target tree.