Application And Optimization Of Individual-tree Model For Plantations Of Platycladus Orientalis In Beijing Area Based On Forest Vegetation Simulator (FVS)

As one of the important afforesting tree species in Beijing mountain area, the area of Platycladus Orientalis in this area was about 25.96% of total forest plantation in Beijing cities.But the plantation of Platycladus Orientalis had a series of ubiquitous problems, such as excessive density,serious differentiation of tree growth, and too slowly tree growing, and so on. In order to make more scientifical and reasonable technology decision-making management for plantations of Platycladus Orientalis in Beijing area. In this paper, Forest Vegetation Simulator(FVS) of America had been researched and resolved earnest. and some issues including constructing site index table for plantation of Platycladus Orientalis, optimizing the diameter growth model, height growth model and volume compute model, forecaseting stand dynamics growth of natural growth and under different management measures were studied by plots investigated and math modeling. The main results were:1) Logarithm curve equation lgH=0.008+0.562lgA was drawn up to match guide curve of site index table for plantations of Platycladus Orientalis. The standard age was 40a, and ten index class were divided out within 4-13m. The test results indicate that the site index table compiled was very accurate and practical which could evaluate the site quality of Platycladus Orientalis Plantation in Beijing mountain area objectively, and improve the accuracy of growth and harvest models.2) Linear models were drawn up to match the relations between outside and inside bark diameter at breast height for Platycladus Orientalis whose datas obtained from 59 parse trees. the bark adjustment factor for Platycladus Orientalis was 1.089 according to the model. Moreover, optimized diameter growth model, height growth model and volume compute model were gained based on the linear models through the methods of regression analysis of the linear regression and the non-linear regression respectively: The examination results indicate that the three optimized models had good fitting and expected effects, and forecasting accuracy were higher than the original growth model.3) Typical stand dynamics growth of natural growth and after kinds of thinning for Platycladus Orientalis had been visual forecast and simulate by appling these models in FVS software. The reasonable forecast results indicated that low and median mechanical thinning of 30-45% was appropriate for the stand whih the ages of 33a, and the density of 3200 trees/hm2 of Platycladus Orientalis plot .The paper results were the basis of improving stand growth dynamics and management technology decision-making level. The fomative site index table and tree growth model for plantation of Platycladus Orientalis can be used for reference for the resemble region.At last, the author suggested that to improve forest growth and yield forecast and management technology decision-making level in China, the researchers around the country should be organized for collaborative research to establish Forest Vegetation Simulator of China.