The Effect of Harvest on Forest Soil N2O Fluxes: A Review

Forest harvests that include clear-cutting, selective cutting, and thinning are widely used management practices. On a global scale, about 30% of forests are harvested to produce timber and non-timber forest products (NTFP). Soil physicochemical properties and microclimate could be altered by forest harvests and further influence soil N2O fluxes. The effects of harvest on N2O fluxes have been investigated under various conditions from the tropics to temperate and boreal forests. The increased, unchanged, and decreased N2O fluxes were observed after clear-cut and partial harvest. Overall, the post-harvest N2O values highly depended on the harvest intensity, soil conditions, and time since harvest. Additionally, the uncertainty of the effects of harvest on N2O fluxes was analyzed from experimental design, statistical method and measurement position. The effects of harvest on the N2O emission to global warming potential (GWP) were also discussed. So far, there have not been many studies in the field and the most focused on temperate and boreal forests. The previous studies also did not pay attention to microbial responses involved in the N2O production. Additionally, informations such as the treatment of harvest residue, the usage of harvest tool types, soil texture and so on, which may interact with harvest on N2O fluxes, were not described thoroughly in the published paper. Overall, the factors regulating N2O fluxes after harvest are still poorly understood.