Evaluation On Benefits And Risks Of Building Camellia Oleifera Forests

This study, on the basis of previous studies, selecting the state-owned forest in Tongkou, Minhou, Fuzhou as the main study area, taking Camellia Oleifera as the study object, analyzes its economic benefits and risks. At the same time, with Camellia Oleifera semis errata and Camellia Meiocarpa planted in the same region as reference objects, on the basis of exploring the three kinds of photosynthetic characteristics of Camellia Oleifera, this thesis analyzes their differences of the abilities of carbon fixation and oxygen release and explores their ecological values. The main study results are as follows:(1) Studies and data analysis indicate that the industry of planting Camellia Oleifera in Minhou has economic benefits to some extent. In a 30-year production cycle and a 8.00% industry minimum attractive rate of return, accumulated net present value of planting Camellia Oleifera is 1771.6846 yuan/mu. Therefore, the profitability of planting Camellia Oleifera project is stronger with over the minimum attractive rate of return,8.00%, and with high additional benefit. The project’s internal rate of return is 14.55%, which indicates that in the current social and economic conditions, the profitability efficiency of planting Camellia Oleifera is 6.55%, higher than the minimum attractive rate of return of other agricultural investment project,8.00%. It shows that the project has good investment value. From the point of view of regional development, the development of planting Camellia Oleifera industry is beneficial to promote local economic development and increase farmers’incomes.(2) In Minhou, the static investment payback period of planting Camellia Oleifera is 9.17 years and the dynamic investment payback period is 12.37 years. Compared with the 30-year growing period, the payback period is shorter. If not consider the time value of capital,9.17 years later you can recover the cost from the investment on planting Camellia Oleifera industry; if consider the time value of capital,12.37 years later you can recover the cost from the investment on planting Camellia Oleifera industry. The short period of investment payback is beneficial to the development of planting Camellia Oleifera industry, which can make the investors earn profits as soon as possible and then attract more investment capitals.(3) By using sensitivity analysis, while other factors fixed, if sales revenues decline by more than 13.25% or production costs increase by more than 13.75%, planting Camellia Oleifera project will face a bigger investment risk. Due to the national policy supporting and government funds spending, the current Camellia Oleifera market is relatively stable that the average market price of Camellia Oleifera is around 110.00 yuan per kilogram-the change of people’s shopping idea has increased the demand for the tea oil. Therefore, under the existing conditions, the development of planting Camellia Oleifera industry has less possibility to incur losses because of factors such as production or price changes.(4) In the sight of testing results of net photosynthetic rate of three kinds of Camellia Oleifera, their seasonal change trend of net photosynthetic rate is roughly:autumn> summer> spring> winter. The daily variation trend of the same variety of Camellia Oleifera in different seasons presents unimodal curve and bimodal curve, and the daily variation trend of different varieties of Camellia Oleifera in the same season is also roughly divided into unimodal curve and bimodal curve. In summer, due to the hot weather, all three kinds of Camellia Oleifera present a bimodal curve. As light intensity increases and temperature rises, the leaf stomata opens and the gas exchange inside and outside is frequent, then plants absorb more CO2 and net photosynthetic rate increases. At around 10:00 to 11:00, net photosynthetic rate reach highest of the day in the first peak; At around 13:00, due to the light intensity is too strong, Camellia Oleifera appears "photosynthetic noon break" phenomenon and net photosynthetic rate is in valley value; After 15:00, external environmental conditions are suitable for Camellia Oleifera photosynthesis, its net photosynthetic rate gradually increases in the second peak. For plants changed in bimodal curve, the afternoon peak is often lower than the morning peak.(5) After the comparison of the simulations of Camellia Oleifera light responses in rectangular hyperbolia model, non-rectangular hyperbolia model, and in rectangular hyperbolia modification model, it comes to the conclusion that rectangular hyperbolia modification model is the best one, whose R2 reaches over 0.98 and more than that of rectangular hyperbolia model and non-rectangular hyperbolia model. At the same time, in the part of the simulation of lower light, Camellia Oleifera all appeared the light inhibition. Only rectangular hyperbolia modification model can simulate the light response curve better that net photosynthetic rate is reduced with the increase of light intensity when light reaches to some intensity. Besides, the predictive value simulated by the rectangular hyperbolia modification model is closest to the measured value. Therefore, rectangular hyperbolia modification model is the best model of simulating the Camellia Oleifera light response curve.(6) The carbon fixation and oxygen release of Camellia Oleifera in different seasons is also different, and the overall performance is autumn> summer> spring> winter, the same seasonal change with net photosynthetic rate.(7) The carbon fixation and oxygen release of Camellia Oleifera in the same season has a big difference, while the change trend of carbon fixation and oxygen release of three kinds of Camellia Oleifera per unit leaf-area and unit land-area is roughly consistent. And the orders of the carbon fixation and oxygen release of three kinds of Camellia Oleifera in different seasons are:in the spring, Camellia Oleifera-Camellia Meiocarpa> Camellia Semiserrata; In the summer, Camellia Oleifera> Camellia Meiocarpa> Camellia Semiserrata; In the autumn and winter, Camellia Meiocarpa> Camellia Oleifera> Camellia Semiserrata.(8) The testing results shows that among different Camellia Oleifera, Camellia Semiserrata has the highest annual average carbon fixation and oxygen release, carbon fixation 59.99 g.m-2.d-1, oxygen release 43.63 g.m-2.d-1; the carbon fixation and oxygen release of Camellia Oleifera and Camellia Meiocarpa is similar, but far less than Camellia Semiserrata.