The Influence Of Harvesting On Carbon Reserve Of Natural Secondary Forest In Northern Fujian

Forest ecosystem is one of the biggest terrestrial ecosystem carbon library, it has have a vital role to regulate the climate. As the increasing of CO2 concentration in the atmosphere, the greenhouse effect has been getting worse. So People pay more attention to the influence of forest management on forest carbon sinks. Harvesting as the primary main for people to get the wood, it impacts on forest carbon stocks in many aspects, such as vegetation volune、the amount of litter、organic content of soils, and so on. After harvesting, forest regeneration is an extension of the forest ecosystem carbon stocks, harvested wood products also store a lot of carbon. It attenuates by using. This artical use long-term dynamic tracing datas to analysis the forest regeneration ability and considering the wood products use and abandoned to analyze the impact on carbon pool by cutting, provide a theoretical basis for the development of forest management measures.The sample plots for this study on selective were set up in Dayuan Forest Logging and Regeneration Station located in Jian’ou County, Fujian Province. In 2006, the natural recovery after 10 years review has completed, we completed the first investigation. And in 2011, we completed the second investigation.Firstly, using the long-term retest datas to derive interval equations by Richard Equation. And then build the individual tree growth equation, the selective intensity as the main factors. Then based on the use of wood products and carbon decay, we establish attenuation model to calculate the carbon stocks in wood products, and evaluate of the different intensity of selective cutting wood carbon pool. Based on Vensim software to make the natural secondary forest carbon dynamics simulation model, and to research and analyze the impace of forest carbon pool by different selective cutting. The results show that:(1) Equation of diameter at breast height and tree height was established by using interval equation. The equation of the fitting accuracy is higher. It provides a good reference for using periodic inventory data to estimate the stand growth dynamic.(2) According to the using of the wood, we build wood carbon decay model. The model results show that the wood carbon is closely related to the intensity of selective. The higher the intensity of selective cutting, the larger the wood carbon. As the paper products attenuation cycle is short. In 15 years, paper products carbon basic will attenuate completely, only wood products carbon left.(3) Using system dynamics theory and method to build the dynamics simulation model. The model is used to research the effects of selective cutting intensity on forest carbon. It is proved to be effective.(4) Improving outturn percentage is one of the effective means to reduce emissions. Data show that the outturn percentage is proportional to the wood carbon. When the outturn percentage increased by 0.19, the cutting wood carbon increased 1.998 t/hm2, equivalent to 6.4% of the timber volume.(5) Hypothesis of maintain the present mode, and considering the vegetation growth and the wood products decay, the carbon in moderate strength cutting plot is more than other plots in 30 years after cutting.(6) According to the sample area vegetation growth equation simulation, we cut trees when the plot volume reach the before cutting volume.100 years as a study period, we predict the carbon in the period. The carbon reserves from big to small is:moderate>weak degrees>strength >extreme strength. So moderate selective cutting is best for carbon sequestration.