The Study Of Stand Spatial Structure Optimization Management And Visualization Simulation For Larix Olgensis Plantation

This study was conducted based on the common characteristics of low mixture degree and uniform distribution of Larix olgensis plantation in a 15-year-old plantation. In consideration from Crown structure and tree competition mechanism, proposed a new method using Crown overlapping coefficient (AO), Hegyi competition index (CI) and Growth space index (GSI) as indicators of spatial structure optimization, the spatial relationship between the tree was described to simulate optimization management of forest spatial structure. According to the data of stem analysis, branch analysis, and knot characteristics from 95 sample trees in 22 sample plots for Larix olgensis plantations with different age, different stand density, and different site, Larix olgensis Crown structure static model and growth model were developed ased on the theory growth equation and the experience growth equation. The combination of structure model and growth model with tree three-dimensional visualization software 3DTree was used to discuss the visual display and management simulation of stand, further analysis the process of thinning Gap dynamic filling. The results are as follows:(1) Crown overlapping coefficient, Hegyi competition index, Growth space index can reflect the quality situation of tree growth similar and can be used as indicators of spatial structure optimization. (2) For 15-year-old Larix olgensis plantation, the optimal thinning intensity is about 15% at which the optimization of forest spatial structure is achieved. After optimization, the forest competition situation reduced, the degree of growth space utilization increased and forest spatial structure got improved. After simulating 20-year-old and 25-year-old optimization management of forest spatial structure, the optimal thinning intensity is about 15% and 10% respectively. (3) Based on the theory growth equation, the static branching structure models, including branch diameter, branch length, angle of origin and branch chord length of primary branches, were developed from branch attributes and tree variables by using the nonlinear regression model. The results showed that these models were suitable for predicting crown branching structure of Larix olgensis plantation. The age factor was introduced in branch static model to establish branch dynamic growth models. (4) Total number of primary branches within a living crown can be directly estimated using single equation, the inverse J-shaped distribution was used to describe the vertical distribution of primary branches and uniform distribution was appropriate to reflect branching pattern around the bole. (5) The Schumacher equation can be used to predict the height of living branches and crown radius dynamic growth, the Korf equation can be used to predict crown length dynamic growth. (6) The gaps formed by thinning trees of 15-year-old stand with the features of small area, short time filled, can be filled in 1 to 3 years. (7) Based on measured data and static model, three-dimensional visualization display of individual tree and stand was achieved. (8) Based on the measured data and the dynamic growth model, forest stand growth dynamics and visualization simulation was achieved.The study developed a new theory and method for Larix olgensis plantation stand spatial structure optimization management. It has some theoretic and practical significance for adjusting the horizontal distribution pattern of plantation stand and improving forest competition relations. The individual tree and stand static and dynamic three-dimensional graphics visualization simulation based on the three-dimensional simulation model of crown structure provided reference for the realization three-dimensional visualization simulation of virtual thinning, stand spatial pattern adjustment and so on.