The Growth Characteristics And Economic Benefit Evaluation Of Castanopsis Hystrix Plantation

In this paper, on the basis of research methods that standard sample plots harvest, stem analysis, combination of static and dynamic economic indicators, 29-year-old Castanopsis hystrix Plantation in Guangxi Liangfengjiang National Forest Park were studied in order to understand it’s biomass accumulation characteristics and distribution pattern, DBH, tree height, volume growth rhythm, production of profit and loss of investment project, etc. All of these provide a scientific reference for the plantation production and management, investment decision of Castanopsis hystrix Plantation. The research results as follow:(1) The biomass of 29-year-old Castanopsis hystrix Plantation was 446.01t·hm-2 in total, in which the tree layer biomass was 440.95t·hm-2, the net productivity was 20.86t·hm-2·a-1. There was overall similarity in the distribution pattern of biomass and productivity between different organs, all the same to the differences.(2) The DBH, tree height and volume of 29-year-old Castanopsis hystrix Plantation were 23.30cm,18.80m,0.3205m3, respectively. The current annual increment of DBH, tree height and volume were all increased with age increase first and then decrease. The fast growth stage of tree height and DBH was just opposite to the volume’s. The fast growing period of DBH and tree height was 0～12th years, while the volume rapid growth period was 12 years after planting and than maintan for a long time. The characteristics of volume growth was benefit to the cultivate of big diameter wood.(3) The growth models have high accuracy of fitting, and the optimal model of DBH, tree height and volume were Richard in the same. It was 40 years before the volume increment achieve the number of mature by the growth model of Richard.(4) The investment project of 29-year-old Castanopsis hystrix Plantation in a state of profit, financial net present value of investment project was 739.43 yuan·hm-2, the financial internal rate of return, the annual investment profit rate and the average annual profit tax rate was 12.29%,17.32%,19.62%, respectively. but the project has a weak ability to resist the risk. The sequence benefit analysis show that the optimal rotation cutting period of Castanopsis hystrix Plantation in economic was 26 years after planting.