The BOREAS TF-04 team measured fluxes of carbon dioxide (CO2) and methane (CH4) across the soil-air interface in four ages of jack pine forest at the Southern Study Area of the Boreal Ecosystem Atmosphere Study (BOREAS) during August 1993 to March 1995. Gross and net flux of CO2 and flux of CH4 between soil and air are presented for 24 chamber sites in mature jack pine forest, 20-year old, 4- year old, and clear cut areas.