Province of British Columbia
MINISTRY OF FORESTS
The British Columbia Forest Service (BCFS) is responsible for managing
One of its objectives is to ensure that these forests are managed as
productively as possible through a province-wide silviculture program.
Just as farmers practise the art and science of agriculture to improve
the productivity of food crops, foresters practice the art and science of
growing trees -- or silviculture -- to improve the productivity of tree
Silviculture in B.C. involves many different activities including:
- harvesting trees in ways that cause little disturbance to the soil;
- preparing new planting sites;
- planting high quality seedlings;
- returning nutrients to the soil by adding fertilizers; and
- managing vegetation, or controlling the growth of various plants to
favour the growth of crop trees.
Vegetation management is, of all the silviculture activities, often the
least understood by the general public. This brochure explains why and how
foresters practise vegetation management in B.C.
|Conifers such as Douglas-fir, hemlock, spruce, pine, cedar and
fir are trees of high commercial value. Just like farm or garden
crops, these trees need generous amounts of light, nutrients and
water to grow well. Yet in the early stages of growth, many less
valuable trees and most brush species provide strong competition for
these essential ingredients. Their growth must be controlled.
The purpose of vegetation management, then, is to promote the
growth of important crop trees by delaying the growth of competing
brush and trees of little commercial value.
The BCFS is giving vegetation management high priority on more
than one million hectares of productive forest land currently
dominated by non-crop growth. Further, the BCFS expects that one
quarter of the approximately 200 000 hectares harvested each
year would return to brush unless appropriate action is taken.
If forest managers do not practice vegetation management in the
context of overall silvicultural efforts, the resulting wood loss
will have serious consequences for the future economy of B.C.
Several years after treatment:
There are five main options for controlling the growth of brush
and trees of low commercial value:
- Manual methods use hand-held cutting tools such as
chain saws, brush axes or girdling tools (used to remove bark from
stems). One advantage is that they can be used selectively to
treat individual trees and brush. However, manual methods are
labor intensive and therefore, expensive. Often, they are
effective for just a short time because cut trees and plants
frequently resprout and may require retreatments. One of the
biggest disadvantages of hand-held cutting tools is the high risk
of injury from sharp blades.
- Mechanical methods use heavy equipment such as crawler
tractors with attachments for mowing, raking, crushing and
chipping. Mechanical methods can be used to clear a large area in
a short time but they are usually limited to preparing sites for
planting. Sometimes they can compact the soil or cause erosion.
They seldom remove plant roots which usually resprout.
- Burning methods are widely used in B.C. to reduce slash
and debris resulting from logging and to control undesirable
vegetation before planting. Burning also improves access for
planting crews and wildlife. It is the least expensive method of
vegetation management but like manual and mechanical methods, it
does not prevent resprouting of undesirable vegetation.
- Chemical methods use herbicides that are registered and
approved for forestry use. They are usually applied through
spraying or by injection. Herbicides often control competing
plants long enough to allow the desired trees to dominate. Because
fewer retreatments are required, chemical methods are generally
less expensive than others. However, no single herbicides can be
used to control all undesirable species.
- Biological methods use living organisms to control
non-commercial vegetation. For example, sheep and cattle are used
to graze on undesirable plants. This is an advantage to both the
forests and the livestock. However, sheep and cattle can sometimes
damage young crop trees. The need for retreatments, fencing,
supervision and protection of livestock from predators, such as
bears, make this method quite expensive.
No single method of vegetation management suits all forest
sites. Each site has its own specific characteristics and its
Forest managers study each site and decide what method of
vegetation management will work best. They may choose a
combination of two or more methods for one site.
When forest managers make a decision, they take into account
First they decide exactly what vegetation should be
controlled and why. They need to know what degree of control is
necessary to favor the growth of preferred trees. They must also
decide how fast and how long this control is needed.
Forest managers study characteristics of the forest site,
such as size, accessibility, terrain and the susceptibility of
soil to erosion or compaction. For instance, forest managers may
find that the terrain is too steep for workers to do manual
cutting or that the soil is too easily compacted or eroded to
use mechanical methods.
Other resource uses are considered when forest managers
choose a method of vegetation management. There may be lakes,
rivers or streams in the area to protect, and fish and wildlife
habitat to maintain. There may be popular hunting or trapping
areas, or aesthetic areas to preserve.
Another important consideration is the health and safety of
both the public and the forest worker. Forest managers will not
undertake any method of vegetation management that places the
worker or the general public in danger.
The choice of method of vegetation management also depends on
very practical matters such as the availability of labor,
equipment and money to do the job. Any choice must recognize and
observe legal or policy restrictions as
Vegetation management is being practiced on forest lands
throughout B.C. as an integral part of the overall silviculture
program. Efforts are being made to:
- return land that is overgrown with brush to productivity;
- protect replanted sites currently threatened by
competition from brush; and
- minimize future vegetation problems on newly harvested
Vegetation management is essential for the establishment and
rapid growth of B.C.'s most commercially valuable trees. Because
it enables the forests to reach maturity in a shorter time,
vegetation management will have a significant effect on the
future economy of B.C.
For more information on Forest Vegetation Management
or a copy of the brochure contact the nearest BCFS regional or
district office or write to:
Forest Practices Branch
Ministry of Forests
PO Box 9513
Stn Prov Govt.