Researches Of Larix Branches Shyness Effect In Stand Growth Simulation

Larix Principis-rupprechtii Mayr is the main tree species of north China, which has many characteristics such as fast-growing, high yield, material quality and so on.But in its study of growth pattern, because of Longer cycle, trees form the structure of complex, difficult to control environmental conditions, growth pattern showed significant regional and temporal and spatial variability, so it is hard to consider multi-factor interaction, forecast growth trend and quantitative management. The paper has physiology and ecology theory of Larix Principis-rupprechtii Mayr as basis, according to the integration of observed morphological structural data from Hebei Saihanba Forest Farm, use the Genetic Programming to simulate, and get the better theoretical stand mean diameter at breast height and stand mean tree height growth functions, Adopt the theory of Collision Detection by the axis-aligned bounding boxes method of hierachical bounding boxes detect branches collision. We consider as branches will spontaneously move up a teeny angle after collision, and get arithmetic of shyness effect and pseudocode and according to algorithm of the shyness effect write environment procedures code to simulate the shyness effect, and with two branches which have same level and different growth rate, we test the algorithm of the shyness effect.We add another two factors Site Index and Afforestation Density to the growth functions in the stand mean diameter at breast height and stand mean tree height growth functions of Larix Principis-rupprechtii Mayr, use the Genetic Programming to simulate. Genetic Programming does not rely on problem domain, not pre-process data, avoid the premature phenomenon of a group of local optimum and not rely on gradient information, that speeds up the convergence rate and the models are simple expression, high-accuracy and wide-applicable. Density of tree is an important factor to impact of forest growth and wood quality, too dense stand of tree will affect the growth of diameter, competition for nutrients will cause the sun partial crown, and at same time the lower crown branches will slowly died because of bad ventilation and light, form the scars in timber; Too sparse stand of tree will make big taper of trees, affect timber volume and hectares of volume, and caused forest waste. The paper divided the shyness effect of branches into collision detection and mobile entities, we use the hierachical bounding boxes to detect collision, which can reduce the number of basic geometric elements as much as possible. We consider that branchers will move upon a very small angle after collision, and get arithmetic of shyness effect and pseudocode. The paper also analyzes the geometrical and topological structures of the whole tree, branche, leaf, leaf bunches and cone, and get the table of morphological structural parameters. We write visual programming by L-system, selecte L-studio which base on graph rewriting as a tool to get the dynamic simulation software branches shyness effects.With the development of information technology, digital forestry is rising. Remodeling modern forestry with digital technology will fundamentally change the tradition and backward, effectively promote the growth patterns of forestry, and adjust and optimize forestry production and the economic structure of forestry. It has great significance to vigorously develop the forestry, solve China's timber sharp contradiction between supply and demand, and improve the environmental quality of human existence.