Microclimate factors.

Low soil temperatures beneath the insulating forest floor typify undisturbed boreal forest sites; as a result, nitrogen is mineralized slowly and thus accumulates as a reservoir in an organic form.  Warming of the forest floor following removal of the overstory by logging or by silvicultural practices has several positive effects on nutrient availability: (1) organic nitrogen is mineralized more rapidly in both the humus layer and decomposing slash, (2) ectomycorrhizal fungi growth is enhanced, as is that of tree roots, both of which increase the area of root-soil contact and thus the absorption of water and nutrients, (3) warmer soil temperatures lower the viscosity of water and improve its ability to move and supply nutrients between root cells.