Effects Of Clear-cutting And Slash Burning On Dynamics Of Carbon And Nitrogen In Chinese Fir And Castanopsis Fargesii Forests

Chinese fir (Cunninghamia lanceolata) is one of the most important plantation tree species in China in terms of planting area, yield and timber usage. The history of managing this plantation exceeds 1000 years in China. In recent decades, many pure Chinese fir stands were established in the southern part of China for an expected highly economic return, leading to a sharp decline in the area of natural forest of broadleaf trees. It is a traditional silvicultural practice in South China to extablish a plantation of Chinese fir by clear-cutting natural forests, slash burning and site preparation. However, timber harvest and slash burning can cause a substantial loss and redistribution of organic matter and nitrogen. Further, yield decline and land degradation in such disturbed ecosystem have become serious problems, possibly due to high precipitations, steep slopes and fragile soils in this region. How the soil fertility can be maintained in the successively planted Chinese fir stands has received considerable concern. In view of increasing awareness about anthropogenic emissions of carbon as a contributor to global warming and the role of forests as C sinks, information about C and N pools and changes associated with disturbances, including forest management, is needed. Especially, a good understanding on how soil CO2 efflux having been impacted by forest management practices is necessary for predicting carbon sequestration. Many attempts have been made, mainly in temperate and tropical forests, to estimate the changes of C and N stored in world forests associated with clear-cutting and slash burning. Littal has been carried out in forests of southern China, a most important area of subtropical forests in the world. Furthermore, few studies have monitored the components of soil respiration before and after disturbance. The aim of this study is to investiagte in detail the effects of clear-cutting and slash burning on the storages of C and N, soil fertility, soil respiration and its components in a Chinese fir plantation and Castanopsis fargesii forest, located in the Yizhou State Forestry Centre in...