Stand-replacing crown fires in boreal spruce forests initiate a vegetation succession from forbs to deciduous trees to coniferous trees. Soils are warmest during the first decades and cool throughout the succession as shading by trees and cover with bryophytes and plant litter increase. It was postulated that the initially warmer soil temperatures enhance decomposition of soil organic matter (SOM) by microorganisms, and that decomposition would release similar amounts of CO₂ as combustion during fire [Auclair and Carter, 1993].