The influence of afforestation and tree species on soil methane fluxes from shallow organic soils at the UK Gisburn Forest Experiment

This is the authors' abstract. We don't add key points for this paper.

There is growing evidence that land use is an important factor in influencing soil methane (CH 4 ) fluxes, and afforestation is viewed as a potential tool for mitigating CH 4 releases from soils. However, the influence of different tree species on soil CH 4 fluxes is not well understood. We measured soil CH 4 fluxes under four tree species and grassland on similar soils at the Gisburn Experimental Forest (NW England) at 2 weekly intervals over 12 months using a static chamber technique. The treatments were Norway spruce ( Picea abies ), Scots pine ( Pinus sylvestris ), oak ( Quercus petraea ), alder ( Alnus glutinosa ) and grassland. Positive soil CH 4 fluxes were observed from grassland plots (average 4.6 kg/ha/year) and negative fluxes from all four tree species (average of all tree species −0.5 kg/ha/year). There were, however, no statistically significant differences between individual treatments. Soil water table depth and moisture content had the greatest influence on soil CH 4 fluxes. It is possible that the afforestation of shallow organic and/or poorly drained soils such as these may have a relatively low capacity for mitigating CH 4 fluxes. Although methanotrophic bacteria may exist (i.e. there is the potential for oxidation), they may not be able to dominate due to their requirements for specific environmental conditions.