Application Research Of Forest Vegetation Simulator To Plantation Of Beijing Region

In this paper, American Forest Vegetation Simulator was well known, and the function,parts, frame of models, flow of operation and input data and output data of FVS were mastered, and base on what we had understood for FVS, explore second-development of FVS according to Chinese forest resource characteristics and apply FVS to Pinus tabulaeformis and Platycladus orientalis of Beijing common species. The aim is to establish a set of individual-tree growth and yield simulation system for Chinese different forest types, and gradually built whole national forest vegetation simulator system, So, provide a suitable reference for Chinese plantation management alternatives. Based on FVS that have be rebuild in China, user can estimate growth and yield of stand according to different management alternatives. The main content of this paper include: (1) study on FVS; (2) study on growth and yield models of FVS in China; (3) new simulator system of Pinus tabulaeformis and Platycladus orientalis based on FVS. The main results as follows:1,study on FVS. FVS that has been developed by USDA Forest Service in the 1970's is a dynamic simulator system for predicting future dynamics changes under current stand conditions and various management alternatives, evaluated hazard ratings for insect outbreaks or wildfires and suitability of stands for wildlife habitat. At present, there are more than 20 variants that represent conditions in a majority of forestland in the United States. According to detailed analysis to the southern variants of FVS, FVS is composed of preprocessor,data transition,SUPPOSE,growth and yield models, postprocessor,Stand Visualization System, keywords and extension, etc. and growth and yield models is most important part.The growth and yield models of FVS southern variants was studied in the paper, it mainly include diameter increment model, height growth model, mortality model, tree crown model and volume model, and the types of growth models mainly is linear regression model, theory growth equations and probability density function, etc. In the same time, Detailed expression of each growth models and calibration methods of parameters of each model were understand. In addition to, through analyzing a lot of case, the flow of FVS operation, input and output data of FVS and how to use keywords were knew. Then, Beijing permanent plot data was used to simulate stand dynamic change under different management alternative to look for some problems about FVS to simulate Chinese forest resourceinventory data, and find out some solving methods, consequently find out a good connection for second-development of FVS.2,Study on growth and yield models of FVS in China. Based on fully studying structure and types of growth and yield models of FVS and methods of adjusting parameter, this paper built the growth and yield models,adjust parameters of each model of Pinus tabulaeformi and Platycladus orientalis in Beijing area. Through collecting and investigating a lot of data, tree crown dynamics change models, individual diameter growth model,individual height growth model,individual diameter-height model and individual mortality model of Pinus tabulaeformis and Platycladus orientalis young and middle plantation were built, at the same time, Site index table of Pinus tabulaeformis and Platycladus orientalis plantation was built.For crown dynamics change models, Crown ratio model,crown width model,crown volume,crown surface area model and crown production efficiency model were studied. Weibull function was used to simulate distribution of crown ratio of Pinus tabulaeformis and Platycladus orientalis stand, and was checked with model of some plot data that not built models through dynamic simulation, the result showed that the observed value of stand crown ratio distribution is not significant difference with simulation value of Weibull function. So, this method can be used in practice. Crown width is simulated by 4 kind of models, and the most accurate one is linear model, CW=0.734+0.174×DBH and CW=-0.311+0.28 ×DBH respectively. In addition to, this paper attempted to estimate stand health through crown surface area and crown production efficiency based on overseas methods, and analyzed distribution rules of individual and stand scale of these index and the relation between crown volume , crown surface area and crown production efficiency and tree diameter in individual and stand scale, developed crown compound index models CROWN=b₀+b₁DBH+b₂BA, and corrected the parameters of individual and stand level. In addition to, 5 percent of observed value statistics distribution was used as thresholds, the result shows the stand is healthy when the average stand CCV>1.08m³ or CCSA>7.22m² or CEFF>1.33.Multi-linear regression function were made use of in the diameter growth models of FVS, therefore, the method is used to simulate individual diameter growth of Pinus tabulaeformi and Platycladus orientalis, and built the diameter regression function between individual periodic diameter increment and site conditions> tree size and competition indexs, Coefficient R² is 0.602 and 0.699 respectively. The relevance is remarkable. In addition to, before building diameter model, site index table of Pinus tabulaeformis and Platycladus orientalis plantation was built in this paper. which fit to whole Beijing area. Using some increment core to test, the result shows that the observed value of height growth is not significant difference with simulation value. So, this site index table can be used in practice.Six theory growth function such as Logistic,Richard,Weibull,Korf,Schumacher and Mischerlich were used to predicting individual height growth. The result shows that adjusting Logistic functionis the most accurate. And the residual of predicting model wasanalyzed, so I think that the model is fit for estimating height growth of Pinus tabulaeformis and Platycladus orientalis plantation under different site condition.Tree mortality model is one of the important tree growth and yield model. In the paper, tree mortality model of overseas and domestic documents widely was studied, and Logistic model was used to model tree mortality of Pinus tabulaeformis and Platycladus orientalis young and middle plantation. Independent variables are DBH,1/DBH, DBH², BAL,DBH²/BA and BA, etc. Using some plot that not built models to carry through dynastic simulation, the result shows that the observed value of tree mortality rate is not significant difference with predicted value. So, this model can be used in practice.3 , Frame system of FVS was studied, the advantage and disadvantage of second-development of FVS was analyzed, and the author find that it is very complex to change growth and yield models of FVS. So, in order to simplify this process of change growth models and parameters and overcome some disadvantage of frame system of FVS, a kind of new frame system Agent was attempted to adopt in the paper, and XML distribution compute model was used. Therefore, the new frame system can simplify changing process of growth models, and quicken the compute process. Finished these work, new growth model of Pinus tabulaeformis and Platycladus orientalis plantation was added to new system of FVS, and to predict stand growth of Pinus tabulaeformi and Platycladus orientalis plantation, the result shows that predicted value of diameter growth,height growth and volume is very closed to observed value. So, the new simulation system of Pinus tabulaeformis and Platycladus orientalis plantation can been applied in practice.