The Research Of Growth Model And Simulation System Of Pinus Massoniana Lamb Plantation

Pinus massoniana Lamb is one of the main plantation in Guangxi Zhuang Autonomous Region,which plays an important role in the development of forestry industry.Based on the theoretical growth model of trees,according to the geographical location and stand information of the study area,this paper introduces the thickness of soil layer and the aspect of slope as dummy variables into the growth model of Pinus massoniana Lamb to explore the impact on the growth model.Based on the established growth model,this paper studies and builds a stand growth simulation system,encapsulates and parameterizes the specific growth model,and uses visualization tools to realize the visualization of simulation results data.The main work of this paper is summarized as follows:(1)Six kinds of basic nonlinear growth models were selected.Firstly,the basic models of average tree height,sectional area and accumulation growth of Pinus massoniana were preliminarily constructed with age and plant density as independent variables.Secondly,the optimal model was selected in the basic model,and the soil layer thickness factor and slope direction factor were introduced in the form of dummy variables to further explore their impact on forest growth.The conclusion is that the prediction accuracy and fitting effect of the growth model based on dummy variables are better than that of the nonlinear growth model.Among them,the accuracy of the average tree height model is improved by 5%(the slope factor was introduced),6%(the soil thickness factor was introduced),the accuracy of the section area model is improved by 5%(the slope factor was introduced),7%(the soil thickness factor was introduced),the accuracy of the accumulation growth model is improved by 6%(the slope factor was introduced),7%(the soil thickness factor was introduced).(2)In order to explore the influence of aspect factor and thickness factor of soil layer on the growth of forest,the aspect factor and thickness factor of soil layer are redivided.Firstly,aspect factor is introduced into the growth model as dummy variable,and then under the same aspect of aspect,the thickness factor of soil layer is introduced into the growth model as dummy variable.After comparing the predicted values under different conditions,the results show that aspect factor is the most important factor The maximum parameters of stand growth model are significantly influenced by the soil layer thickness factor,which is more favorable for the growth of Pinus massoniana Lamb under the same slope direction.Conclusion it is consistent with the characteristics of light,temperature and deep root system of Pinus massoniana Lamb.(3)Based on Python Tornado Web framework,a stand growth simulation system was developed.The system adopts the multi-layer development mode of MTV,takes Tornado as the back-end framework,and combines with the Py Echarts visualization component to realize the core function modules of stand growth simulation and data visualization.In this paper,the stand growth model of Pinus massoniana Lamb plantation was studied,and the growth simulation system based on Web was built,which can help the management decision of Pinus massoniana Lamb plantation.