Denitrification rates were measured as N₂O production in two water-logged forest soils at monthly intervals. The effect of acetylene inhibition and the addition of nitrate, glucose, acetate and celloboise in field incubations was examined. N₂O release from the two soils was very low, 26 mg N₂m^-2y^-1 in ash and 178 mg N₂ in alder. In acetylene inhibited incubations N₂O production was higher, 296 and 486 mg N₂m^-2 y^-1 in ash and alder respectively. After addition of nitrate and C-sources to a 10 mM concentration, denitrification rates increased to 5-15 times higher values. The denitrification rates below 4°C were low and most N₂O was produced in late spring and summer. The highest rate of denitrification during a 50 h incubation experiment occurred between 3 and 23 h.