GREENHOUSE GAS (GHG) EMISSIONS AND THE OPTIMUM OPERATION MODEL OF TIMBER PRODUCTION SYSTEMS IN SOUTHERN CHINA

摘要

Deforestation as an activity of forest management is an intermediate link in timber production. Different models of timber production make a difference in GHG emissions and to a certain extent affect the sustainable development of the ecological environment. Accordingly, due to global climate change, energy conservation and emission reduction have become critical issues concerning all humans. This paper taking the operating systems of timber production in the southern China, as a case study, and GHG emissions and the optimum operation model of timber production are analysed with the B2B model of life cycle assessment (LCA) and the current forest industry standard. The results indicate that the total emissions of GHG range between 11.600 9 kg/m(3) and 15.303 6 kg/m(3), accounting for approximately 4.5 percent to 5.5 percent of their carbon sequestration abilities. Direct GHG emissions generated by fuel consumption during harvesting, skidding, loading, transportation and production are the primary emissions, accounting for approximately 69.1 percent to 91.5 percent of the total emissions. Moreover, the emission of every type of GHG is lowest under model IV (which included chainsaw cutting, cableway skidding, winch loading, diesel vehicle transportation and vehicle transmission). From the perspective of ecology, therefore, model IV is the optimal operation model. On the other hand, the emission from timber transportation is highest, accounting for approximately 61.5 percent to 72.3 percent. Therefore, appropriate operation models should be choose according to the mechanical production and management, production tasks and scales, foundations of forest mechanization and economic conditions. In terms of carbon reduction, improvement of the mechanical equipment efficiency, operation skills and utilization of new energy resources should be considered.