The Three Dimensional Computer Graphics Simulation Technique Of Tree Grown Dynamic For Mongolian Scots Pine In Plantation

This study was performed in Mongolian scots pine(Pinus sylvestris L.var.mongolica Litvin)plantations in Maoershan experiment forest centre of Northeast forestry university. Based on stem and branch analysis,data were collected from 53 sample trees in 15 plots with different age,site condition and density in 2002 and 2003.The variables of 2298 branches were measured in this paper,which included depth into crown,branch azimuth,branch angle, branch diameter,branch length,branch chord and height of branch bow.Based on theory and experience growth model,the crown static models and dynamic growth models of Mongolian scots pine plantations were developed in this study.The crown three-dimensional visualization dynamic graphics simulation system of Mongolian scots pine was established on the developing platform of VC++6.0 language and OpenGL through the combination of growth model and configuration structure model.The visualization simulation of static and dynamic single tree and stand based on actual measurement data and growth model was realized in this paper.The study of crown three-dimensional visualization simulation based on growth model was performed from two aspects in this paper.One is to develop the crown static and dynamic models based on field actual measurement data;the other is to realize the simulation process using programming language.The contents of this paper were as flows:1 The establishment of crown static models of Mongolian scots pine,which were performed from the aspects of crown form model and structure model.The best models for predicting branch diameter and length of Mongolian scots pine were established based on the actual measurement data using the variables of depth into crown of the branch(DINC),tree diameter at breast height(DBH)ant tree height(HT).The precision of the models for predicting branch angle was too low but branch angle increased with the increasing of DINC. The general distribution of branch angle was described in this paper.The study of crown structure model includes the establishment of the models of predicting branch number and the space distribution.The results showed that the branch number in a whorl decreased along with the increasing number of adjacent whorls in effective crown.The branch number had a linearly decreasing with the increasing of DINC below the effective crown.The branch horizontal distribution can be fitted by circle proportional distribution and the circle distribution statistic was useful for analyzing the branch azimuth.The study of the space distribution of branch can provide base for the dynamic simulation for the crown structure of Mongolian scots pine plantation.The models of whole leaf biomass of a tree and single branch based on stand and forest factors were established and the vertical distribution of leaf biomass in the crown was studied in this paper.The result shows that diameter at breast height(DBH) and crown length(CL) were best variables for establish the model of total leaf biomass;the leaf biomass of single branch was relation with branch diameter(BD),branch length(BL) and branch relative height in crown(BRH) and their log transformation were the best predictors;the vertical distribution of leaf biomass can be described use Weibull distribution function with 2 parameters.The scale parameters b ranged from 0.47 to 0.72 and the shape parameters c ranged from 2.01 to 4.52;all the sample trees past through t test and the correlation index were all over 0.95(ranged from 0.958 to 0.997);the shape parameter c of 26 sample trees in all the 36 sample trees contains 3.6 at the confidence interval of 95%,which shows that the leaf biomass of these sample trees obey normal distribution.i.e.the leaf biomass of most sample trees centered at the middle of crown and the leaf biomass of suppressed trees were often at the upper part of crown to obtaining more light to maintain tree activity.2 The establishment of crown structure dynamic models of Mongolian scots pine plantation.Based on the crown static models,the dynamic growth models of branch diameter and length were established by inducting branch age into theory growth model according to the branch analysis data of branch diameter and length growth data to reflect the crown structure dynamic.The branch diameter and length growth were mainly related with DBH and HT.It was necessary to establish the dynamic growth models of DBH and HT to study the crown dynamic. The Richards theory growth model was selected according to dynamic data of DBH and HT obtained by stem analysis and checking whorl height.The correlation index of all the sample trees were above 99%,which showed that the selected models were suitable for predicting the growth of DBH and HT.The dynamic of height of the first alive branch and crown length was predicted using the dynamic growth model provided in existing dissertation.The precision of the referenced models was tested.3 The crown three-dimensional visualization dynamic graphics simulation of Mongolian scots pine based on the measurement data and growth model.The simulation software (3DTree 1.0v) was developed based on the software of OpenGL 1.4 and VC++6.0 adopting simple geometry modeling method.The software can be operated by inputting few parameters and reading data files,which were the Excel file of measurement data and the files created by the growth model.It can rebuild the static three-dimensional graphic of single tree and stand based on measurement data.It also can simulate the static and dynamic three-dimensional graphic of single tree and stand based on the growth mode to provide reference for the visualization management and landscape design,such as suppositional cutting and training.The study in this paper can provide theory base and management method for the development and application of Mongolian scots pine plantations so as to get more ecology and economy benefit and improve the management level of Mongolian scots pine plantations in our country.