A major part of Finnish forests are mixtures of conifers
and hardwoods, mainly birch. Pure natural pine stands are
common on only the poorest of dry sites. Scots pine and birch
as light demanding species form single storey stands.
Norway spruce, as a shade-tolerant species, can also grow
under birch or pine shelter. The planting of more than one
species is usually not needed. Birch is regenerating naturally,
especially in young pine and spruce stands, especially after
soil preparation. Spruce will easily arise in birch stands after
thinnings. Whenever the upper tree storey is vital and capable
to produce merchantable wood, the stand will be treated as
two-storied mixture of birch and Norway spruce