One system that is considered successful
on certain site types from a silvicultural as
well as an environmental point of view is the
shelterwood system (H° anell, 1993; Hannerz
and H° anell, 1997). At present, this system
is used mainly in localities with regeneration
problems, e.g. where the seedlings are
likely to suffer from early summer frosts,
rising water-tables and competing vegetation
after logging. Shelterwoods can also be
expected to have positive effects on ecological
maintenance and biological diversity since
the ground is never left bare and exposed
to extreme wind, temperature and moisture
conditions (see for example, Hannerz and
H° anell, 1997).