Effects of clear-fell harvesting on soil CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O fluxes in an upland Sitka spruce stand in England

Abstract. The effect of clear-fell harvesting on soil greenhouse gas (GHG) fluxes carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) was assessed in a Sitka spruce forest growing peaty gley organo-mineral northern England. Fluxes from the litter layer were measured monthly by closed chamber method chromatography over 4 years two mature stands, with one area harvested after first year. Concurrent measurements temperature moisture helped to elucidate reasons for changes fluxes. In 3 felling, there significant increase temperature, particularly between June November (3 5 ?C higher), moisture, which 62 % higher felled area, these had pronounced effects GHG balance addition removal trees their input soil. Annual CO2 effluxes reduced almost third year felling (a drop 24.0 8.9 t ha?1 yr?1) half second (mean 11.8 compared before while those unfelled little changed. N2O more than doubled (from 1.0 2.3 2.5 CO2e yr?1, respectively), although they only 20 (1.2 yr?1). CH4 changed small net uptake ?0.03 yr?1 efflux increasing 0.34 presumably because wetter felling. Soil dominated annual emission when three gases using global warming potential (GWP), but contributed up this. This study showed CO2, CH4, responded differently clear-felling due biotic abiotic factors large variations years. demonstrates need multi-year all GHGs enable robust estimate phase managed forests. is very few monitoring studies assess