马尾松人工林全生命周期化石能源消耗和温室气体排放评估OA

Against the backdrop of the carbon neutrality initiative,plantations are widely regarded as important carbon sinks.However,fossil energy use,soil disturbance,and residue decomposition during their management constitute significant carbon sources,resulting in uncertainties in their carbon sequestration benefits.This study focuses on Pinus massoniana plantations in a typical state-owned forest farm in Guangxi.Using the life cycle assessment(LCA)approach and the global warming potential(GWP)method,we quantified the energy consumption and greenhouse gas emissions throughout the entire process from site preparation and afforestation to harvesting and transportation.By incorporating the basic wood density and carbon fraction,this study quantified the carbon sequestration efficiency per unit timber volume and further extrapolated the national-scale carbon sink capacity of P.massoniana plantations.In addition,the spatial distribution of carbon emissions,sensitivity characteristics,and the sequestration potential of P.massoniana were comprehensively analyzed.The results are summarized as follows:1)Producing 1 m3 of roundwood required an energy footprint of 60.41 L/m3 diesel and resulted in a carbon footprint of 14.45 kg(CO2-eq)/m3,with an annual emission intensity of 2 192.98 kg(CO2-eq)/hm2.2)Carbon emissions mainly originated from soil disturbance(35.11％),diesel consumption(32.12％),residue decomposition(17.64％),and compound fertilizer application(13.73％),with site preparation and land clearing together accounting for over 58％.Transportation contributed less than 5％of carbon emissions,which was substantially lower than that of transportation-dominated systems in Europe and North America.3)System emissions were most sensitive to diesel consumption and site preparation,with sensitivity coefficients of 0.67 and 0.39,respectively,followed by fertilization inputs,and the impacts of labor and pesticides were minor.4)The nationwide net carbon sequestration was estimated at approximately 880 Tg(CO2-eq),with an average annual net sequestration rate of about 46 Tg(CO2-eq).Each cubic meter of roundwood can store 0.821 t(CO2-eq),which exceeds that of some European coniferous forests,indicating a strong carbon sequestration potential.The study revealed the coexistence of emissions and carbon sequestration throughout the life cycle of P.massoniana plantation management and identified priority intervention stages,providing a scientific basis for low-carbon management and the improvement of carbon accounting systems in plantations,while also laying a foundation for subsequent multi-regional long-term monitoring and scenario simulations.