Assessment of winter fluxes of CO2 and CH4 in boreal forest soils of central Alaska estimated by the profile method and the chamber method: a diagnosis of methane emission and implications for the regional carbon budget
International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775-7335, USA;;Division of Earth and Planetary Science, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan