clearcutting reproduces a new even-aged stand by completely removing the mature stand.
clearcutting as a silvicultural treatment has several characteristics:
it causes a sudden environmental change
it removes the seed source from the regeneration area
the configuration of the clearcut may affect seed dispersal
it begins a new rotation
it will eliminate some pests that require forest cover
overall, it temporarily removes the forest cover, transforming the forest community and environment.
clearcutting followed by artificial (seeded or planted) regeneration has several advantages:
we can avoid delay in restocking the site
we can introduce a selected species, seed source, and genotype
we can control arrangement and spacing
we can achieve uniformity in the new stand
we can overcome the problems associated with securing sufficient natural regeneration.
the shelterwood method involves the removal of most of the mature stand at the end of the rotation, but a portion of the mature stand is left standing. the shelterwood method serves three basic purposes:
to prepare the stand for production of abundant seed
to modify the environment in a way that promotes germination and survival of the selected species
to build up the amount and size of advance regeneration to ensure the prompt restocking of the new stand following overstory removal.
the shelterwood method involves a sequence of 3 cuttings:
preparatory cuttings: make the seed trees more vigorous and set the stage for regeneration. see our thinning page for more information.
establishment/seed cuttings: open up enough vacant growing space to allow establishment of the new regeneration.
removal cuttings: uncover the new crop to allow it to fill the growing space.
the residual trees in the shelterwood must:
be sturdy and windfirm
be able to survive exposure
flower and reproduce seed
be the best trees of the mature stand
keep in mind that the shelter trees must not occupy the entire site. a void must be created in order to make room for the new regeneration. the amount of shelter to leave will depend on the following factors:
species characteristics (seeding and shelter requirements)
the number of cuttings in the cutting sequence (1, 2, or 3)
the size of the area to be regenerated
the final removal harvest level required to be profitable
the shelter must be removed before it impedes the growth of the new stand or threatens its survival.