The Rural Voice, 2004-10, Page 50a
Woodlot Management
Examining silviculture sgstems
Steve Bowers
is a forester
and forest
owner, a
member of
the Huron -
Perth
Chapter of
the Ontario
Woodlot
Association
and
Stewardship Co-ordinator with the
Huron Stewardship Council.
Last month's column discussed
shade tolerance of various tree
species. This trait is one of the key
factors influencing the silvicultural
system most appropriate for a forest
area.
Some readers may not be familiar
with the terms silviculture or
silvicultural system. Most are no
doubt familiar with the word
agriculture which is derived from the
Latin term ager (relating to fields)
and involves the culture of crops
(usually in fields). The term
silviculture is derived from the Latin
term silva (relating to wood or forest)
and involves the culture of forest
crops.
An agricultural system includes a
series of management actions that
ideally allows production to continue
in a sustainable fashion. Similarly, a
silvicultural system involves a series
forest management activities carried
out in order to maintain the forest in a
sustainable, productive state to ensure
BERNIE McGLYNN
LUMBER LTD.
BUYER OF HARDWOOD BUSHLOTS
Wholesaler - Hardwood Lumber
Box 385, R.R. 2,
Wingham, Ont. NOG 2W0
BERNIE McGLYNN
Ph/Fax (519) 357-1430
SAWMILL -
R.R. #5, Mildmay, Ont.
(519) 367.5789
46 THE RURAL VOICE
•
•
•
•
•
••
'Mr..
continued provision of multiple forest
benefits, including wildlife habitat,
recreational opportunities, clean
water and forest products. The three
most common silvicultural systems
are single tree selection, shelterwood
and clearcut.
Silvicultural systems tend to focus
on the approach taken when trees are
harvested and, to a certain extent,
attempt to emulate the type of natural
disturbance that would have been
common in the forest prior to
settlement. For example, one of the
most common forest types in
southwestern Ontario is upland
tolerant hardwoods including species
like sugar maple and beech.
Typically these stands are best
managed using a single tree selection
system, assuming the management
objectives include maintaining shade
tolerant species in the stand. Under
the selection system individual trees
are removed at regular intervals,
mimicking the natural loss of
individual trees or small groups of
trees in a natural stand, while
maintaining a minimum level of
stocking and keeping appropriate
representation of trees in all size
classes. As a result, trees of a variety
of sizes may need to be removed
during cutting to maintain the
optimum distribution. This approach
maintains an uneven -aged forest,
meaning trees of several age and size
classes are present. Poorer quality
trees are icmoved wherever possible
(with appropriate consideration for
wildlife and other values) to
concentrate growth on the best
quality stems.
If regeneration of species that are
less shade -tolerant such as red oak or
black cherry is desired, the
shelterwood system may be more
suitable. In the shelterwood system
the larger trees are removed in a
series of partial cuts. The conditions
are more open than would be seen in
the selection system, mimicking more
severe natural disturbances that
favour establishment and growth of
Tess tolerant species. The series of
cuts is designed to encourage natural
regeneration and rapid growth of
these intolerant species, while still
providing some protection by the
partial canopy. Once the young stand
is well established, the remainder of
the original trees are removed. The
shelterwood system tends to result in
an even -aged forest.
Clear cutting is a system that
many people have heard of or have
seen in northern Ontario. It has
received much bad publicity in the
past, often justifiably. It is seidom an
appropriate system for use in
southern Ontario for a variety of
environmental, aesthetic, ecological
and silvicultural reasons. However, it
is an appropriate system for shade
intolerant species such as jack pine
forests in northern Ontario that have
evolved to respond to major
disturbances like forest fires.
Foresters have made significant
advances in the use of clear cuts in
recent years. Considerable effort is
now made design them in a way that
emulates natural disturbances.
Typically they are now carried out in
smaller patches, with irregular
boundaries creating cutovers that are
more ecologically and aesthetically
acceptable. A variety of treatments
such as planting or prescribed
burning may be necessary to
regenerate the stand. Clear cutting
obviously results in an even -aged
forest.
There are also many other factors
besides shade tolerance that may
influence the appropriate
management approach. Perhaps I can
touch on them in future columns.
If you have questions about
woodlot management or ideas for
topics you would like to see covered
in a future column, please contact
Steve Bowers at 519-482-3661 or
steve.bowers @ mnr.gdv,on.ca.0