Forest Pests
A healthy forest is able to sustain itself ecologically while providing for society’s
economic, social, recreational and spiritual needs and values. Forest health is
a term used to describe the condition of a forest and how well it is able to meet
management objectives. From a forestry perspective, management objectives focus
on the health of the trees.
The Crown and the forest industry are jointly responsible for protecting Alberta’s
forests from pests. The Department of Sustainable Resource Development (SRD) ensures
maximum benefits from Alberta’s forests, in part, through an effective forest health
program. Healthy forests provide:
- a cleaner environment
- healthy biodiversity
- a higher quality of life for all Albertans to enjoy
- improved recreational opportunities
- sustainable fibre resources
Alberta’s forest health program monitors key biological, physiological, and environmental
factors that may have an adverse effect on the health of the forest. These factors
can include:
- birds
- insects
- mammals
- microorganisms (bacteria, fungi)
- nematodes
- non-infectious disorders caused by climate, soil, applied chemicals, air pollutants
and other physiographic conditions.
- noxious and restricted weeds
- parasitic plants
Pest detection, survey and monitoring, risk and impact assessment and management
programs in forest stands help maintain forest health. Forest pest management is
a systematic approach to reducing pest damage to socially and economically acceptable
levels.
What is a forest pest?
Many factors can have negative effects on the health of a forest. Some are biotic
or living. Others are abiotic or non-living.
Biotic factors
- disease-causing organisms
- insects
- parasitic plants or mammals
|
Abiotic/non-living factors
- drought
- severe weather events (hail, ice storms)
|
When some organisms threaten the overall health of the trees or compete with us
in the use of the forest, we identify them as pests. Typically, pests are organisms
that occur in intolerable numbers in unwanted places. They can threaten a forest
by damaging the trees and environment that people think are valuable.
What are the top ten most threatening pests to forestry?
- Mountain pine beetle and invasive alien insects or diseases
- Spruce beetle
- Spruce budworm
- Aspen defoliators
- Armillaria root disease; hypoxylon canker; Atropellis canker and tomentosus root
rot
- Lodgepole pine dwarf mistletoe and Western gall rust
- Terminal weevils
- Root collar weevils
- Stem and Wood Borers
- Cone and seed feeders
For more information on these various forests pests, see:
How do forest pests affect forestry?
Depending on the forest pest, it can target all tree species, few tree species or
just a given tree species of a certain age in a forest. Young or mature/overmature
trees are the most vulnerable to forest pests. Forest pests that attack young trees
can have a significant long-term impact on the future forest. The forest industry
relies on the quality of the mature trees it uses; therefore; forest pests that
attack mature trees compete with the forest industry.
Forest pests can slow down tree growth and vigour. Some can eventually kill the
trees. Others can reduce the fibre quality and appearance. Forest insects and diseases
accounted for 36 per cent of timber volume loss in Alberta between 1988 and 1992.
During this period, forest pests destroyed, on average, an estimated 7.3 million
cubic metres of timber each year (Brandt 1995). This was equivalent to 47 per cent
of the timber volume annually harvested during the period.
Brandt, J.P. 1995, Forest Insect and Disease-Caused Impacts to Timber Resources
of West-Central Canada, CFS, Information Report NOR-X-341.
Why are forest pests becoming more important?
Alberta must deal with two major long-term issues that can affect forest health:
- aging forests
- potential climate warming
Aging Forests
In the next 20 to 30 years, Alberta will face the problem of aging forests. Currently,
over 60 per cent of Alberta’s deciduous, pine and white spruce forests are in the
over 60-year, over 80-year and over 100-year mature age classes, respectively. If
the current trend continues, within the next 30 years, over 80 per cent of these
species would be in the overmature age class. This pattern could be modified if
there were a change in the frequency and severity of wildfire and rate of harvests.
Naturally, an aging population is more vulnerable to insects, diseases, adverse
environmental conditions and forest fires. An abundance of overmature forests will
provide added possibilities for major outbreaks of forest pests.
Potential Climate Warming
Historical climate records in Alberta indicate a warming trend in the last century.
It is reasonable to assume that this trend will continue for the foreseeable future.
Many forest pest species in North America are expanding their ranges into more northern
regions. For example, the mountain pine beetle now occurs further north in Alberta
than ever before. This suggests that the pests are adapting to new environments
or that the region is becoming warmer. Evolutionally, pests can adapt to new environments
in a relatively short time. Combined with global warming, this could lead to ever
increasing outbreaks, especially if these processes are synergistic.
Alberta Environment Climate Change suggests that insect pests expand into new habitat
ranges much faster with changing climate than forests can acclimatize. As these
pests would be new to the forests, trees would not have natural defences against
them. Native insects in new ranges would have the potential to do as much damage
as invasive foreign pests.
In light of possible climate warming, SRD, the forest industry and other federal
and provincial agencies must work together to implement a strategy to rejuvenate
Alberta’s forests and create healthy, vigorous forests that can withstand catastrophic
forest pest outbreaks and wildfires in the future.
What can be done?
Alberta’s forest inventory reflects yields from forests that have been largely unprotected
from pests. A more aggressive approach to pest management could increase fibre yield
from Alberta’s forest resources. Minimizing losses from forest pests is one of the
most economically, environmentally and socially acceptable approaches to increase
fibre yields.
The current harvestable forested area is approximately 40 per cent of Alberta’s
forested Crown land. Harvesting alone will not effectively rejuvenate aging forests;
therefore, prescribed fires must be introduced to the landscapes. A combination
of strategic harvesting and vigorous prescribed fires are essential to avoid future
catastrophic events.
Catastrophic forest fires and pest outbreaks are symptoms of unhealthy forests.
Wildfire prevention and integrated pest management programs need to focus on forest
health improvements by rejuvenating Alberta’s forest landscapes.
Most of Alberta’s forest fibre resources are currently managed by the forest industry.
The forest industry (Forest Management Agreement and Timber Quota holders) is given
the authority to make management decisions within a framework of sustainable forest
development. Therefore, an integrated pest management approach and forest management
planning provide opportunity for the forest industry to improve forest fibre productions.
Important pests such as the mountain pine beetle, spruce beetle, spruce budworm
and dwarf mistletoe can be proactively managed so that extensive tree mortality
and salvage operations can be avoided and impacts on the annual allowable cut minimized.
Are there acts and regulations that guide pest management?
Yes.
The Forest and Prairie Protection Act establishes regulations with respect
to forest pest and fire control, prevention and education in the forested and prairie
land in Alberta.
The Environmental Protection and Enhancement Act supports and promotes protection,
enhancement and wise use of environment while recognizing, among other things, principles
of sustainable development to ensure that use of resources today does not impair
prospects of their use by future generations. This act governs the Environmental
Protection and Enhancement Fund, the Revolving Fund and the Environmental Protection
Security Fund for emergency use.
The Alberta Agricultural Pests Act and the Weed Control Act, administered
by Alberta Agriculture and Rural Development, provide guidance for forest pest management,
including invasive species such as weeds.
The federal Plant Protection Act prevents importing, exporting and spreading
of pests that may damage existing plants in both Agriculture and Forestry Sectors.
This act provides the basics for control and completely getting rid of these pests.
It also regulates how plants are certified. Also, the Canada Seeds Act controls
inspections, testing, quality, and sale of seeds in Canada.
For more Information about forest management standards and practices, see:
Posted: June 10, 2009