Advances of study on atmospheric methane oxidation (consumption) in forest soil

Next to CO 2 , methane (CH 4 ) is the second important contributor to global warming in the atmosphere and global atmospheric CH 4 budget depends on both CH 4 sources and sinks. Unsaturated soil is known as a unique sink for atmospheric CH 4 in terrestrial ecosystem. Many comparison studies proved that forest soil had the biggest capacity of oxidizing atmospheric CH 4 in various unsaturated soils. However, up to now, there is not an overall review in the aspect of atmospheric CH 4 oxidation (consumption) in forest soil. This paper analyzed advances of studies on the mechanism of atmospheric CH 4 oxidation, and related natural factors (Soil physical and chemical characters, temperature and moisture, ambient main greenhouse gases concentrations, tree species, and forest fire) and anthropogenic factors (forest clear-cutting and thinning, fertilization, exogenous aluminum salts and atmospheric deposition, adding biocides, and switch of forest land use) in forest soils. It was believed that CH 4 consumption rate by forest soil was limited by diffusion and sensitive to changes in water status and temperature of soil. CH 4 oxidation was also particularly sensitive to soil C/N, Ambient CO 2 , CH 4 and N 2 O concentrations, tree species and forest fire. In most cases, anthropogenic, disturbances will decrease atmospheric CH 4 oxidation, thus resulting in the elevating of atmospheric CH 4 . Finally, the author pointed out that our knowledge of atmospheric CH 4 oxidation (consumption) in, forest soil was insufficient. In order to evaluate the contribution of forest soils to atmospheric CH 4 oxidation and the role of forest played in the process of global environmental change, and to forecast the trends of global warming exactly, more researchers need to studies further on CH 4 oxidation in various forest soils of different areas.