Patterns of undisturbed nutrient cycling in northern ecosystems and the impact of fire on nutrient cycling are reviewed and discussed. The various effects of fire on ecosystem nutrient cycling may be broadly subdivided into (1) nutrient redistribution during fire, and (2) changes in post-fire nutrient cycling. Effects during fire include the loss of nutrients (especially nitrogen) from ecosystems through volatilization, loss of particulate matter in smoke, and convection action; the transfer of mineral elements to the ash layer; and heating of biomass (often above lethal levels) and the upper soil layers. Post-fire changes include the 'pulse' addition of nutrients in the ash layer immediately after fire, possible increased leaching into the soil profile, overland flow or erosional transfers of nutrients, increased soil pH, lowered albedo from the fire-darkened surface, increased active layer depth, and warmer soil profiles which affect microorganisms and decomposition processes. The magnitude of these effects is discussed in the light of our present knowledge and needs for future research are proposed.