Les liens entre
les pratiques
forestières et
la santé

 

 

 

 

 

 

 

 

 

 

 

 

 


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For a complete
list of the resources used
to develop this article, please contact the
Community Animation Program at 1-800-663-5755
email

David Suzuki Foundation 
The article, "Forestry Data Shows Need for More Economic Benefits and Jobs" shows the relationship between jobs and timber production in different countries. Canada has one of the lowest ratios. It is available in the forestry information 
bank

Forestry:
Key Issues

explains how high value products will benefit both communities and the environment through enhan-
ced economic opportunities.
Ecoforestry: 
The Art and
Science of Sustainable Forest Use.
Drengson, Alan and Duncan Taylor (eds.) 1997.
Gabriola Island, BC: New Society
Publishers. 

This book provides a reference-style approach to the principles, policies, and practices of an ecological alternative to the current forest
industry, including ecosystem management and restoration, community
forestry, deep ecology, and forest product certification.

Earth Island Institute (EII) 
300 Broadway, Suite 28, San Francisco, CA 94133, Tel: 415.788.3666, Fax:415.788.7324 Email
"EII fosters the work of creative individuals
by providing organizational support in developing projects for the
conservation, preservation, and restoration of the global environment."

Ecoforestry Institute Society of Canada 
is dedicated to promoting
ecologically, socially and economically responsible forest use that maintains and restores the complexity and diversity of our forests.  They have an excellent web site, and
produce a journal Ecoforestry (formerly known as the International Journal of Ecoforestry). Many of the articles include discussions of what ecoforestry is, and the links between forestry
and economic opportunities.
To get a sense of the value we get from forests,
read: 

How Much is a Forest Worth?
 
Wittbecker , A. 1998.
 
International Journal
of Ecoforestry
, available on the web site. 
Another must-see article is
Wildwood by Merve Wilkinson
An example of what's possible in the forest.
This essay from practical experience shows how selection forestry can be
sustainable over the long term, and help more people make a living. 

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(photo: CAP Atlantic)

 

 

 

 

       

Links between
Forestry Practices
and Human Health

Community Animation Program Atlantic
Jennifer Scott, Environmental researcher and organic farmer
August 2000

here was a time when people were deeply connected with their natural surroundings. They were completely dependent on the


(photo: Community Animation Program Atlantic)

knowledge of the forest with all its parts: from the tiniest fungus, to the movement and flow of water and large mammals. In recent years many of us have lost our connection with, and knowledge of, the forest.

The health, condition, and management of a forest can have significant impacts on the health of people. Forest cover and structure profoundly affect the quality of the water and the species that live in it; this affects our health. Employment opportunity affects our well-being, and the management of forest resources affects those opportunities. Certain management practices also threaten wild food and medicinal herbs that are often abundant in forests. Herbicide and insecticide applications and road construction will also affect our health. We are experiencing changes in weather patterns that are affected by global forest cover and use. There is no escaping it -- we are still integrally connected with the trees and forests around us.

Health and Environment Issues
Relating to Forestry

Water and Soil Quality

Forests, riparian strips, wetlands, and cattail ponds are all responsible for filtphoto: CAPering, cycling, and regulating water. Many studies show that water quality diminishes as trees and natural features are removed or changed. Practices associated with forestry, such as road-building, stream crossing, nutrient leaching, soil erosion, and pesticide applications all have negative effects on water quality. Good health is fundamentally based on access to clean, unpolluted water that our natural areas provide.

Food Security: 
Wild Food, Medicinal Herbs, and 
Keystone Species

Diverse and healthy forests provide important opportunities to use wild food and medicinal plants such as blue cohosh (a hormone regulator), goldthread (for its anti-cancer properties), or greens, mushrooms, nuts and fruit. Many of these species will not grow after the forest is clearcut, or take years to re-establish themselves. Also, forest productivity can be dependent on interactions we don't even know about. Tree productivity, for example, is based on the relationship between tree roots and soil fungi. Without its associated truffles and mushrooms, a tree will grow at a much slower rate. Species such as flying squirrels spread these fungal spores by eating truffles and leaving pellets behind. Flying squirrels, however, do not thrive in post-clearcut forests.

Employment Opportunity

It has been firmly established that economic opportunity is a major determinant of health. A resilient forest with a wide range of species can translate directly into dollars from forest products and savings from all the services a forest provides (e.g. ground water purification, carbon storage, air purification, cooling and shade, house insulator, and ecology teacher). Forests also provide opportunities for tourism, recreation and spiritual pursuits. According to Environment Canada, they support a multibillion-dollar recreation and tourism industry.

Toxic materials

The forest industry uses many toxic compounds and produces toxic byproducts so that we can have white paper and building materials. Pesticides (which includes herbicides, insecticides, and fumigants) are used in seedling nurseries and cut over areas for re-planting operations, and in forests for insect pest control. According to Environmentphoto: CAP Canada, the biggest known users of insecticides in Atlantic Canada are the provincial governments of New Brunswick, Nova Scotia and Newfoundland, which spray them from aircraft to combat the spruce budworm and the hemlock looper. Diesel oil and gas are used by machinery when trees are clearcut and transported to mills. At pulp mills, chlorine is often used for processing and bleaching. Pulp mill effluent often contains one of the most toxic sludges known because there are dioxins and furans present. Dioxins and furans have been linked to problems with endocrine and immune system disruption, and cancer.

Fortunately, some of the most potent pesticides are no longer used in the region, but effects of past spraying operations are still with us. In addition, commonly used pesticides that were thought to be very safe (such as Glyphosate) are, upon further scrutiny, scheduled for bans in Europe because of documented negative health effects. The question "is glyphosate safe?" will produce widely different answers, depending on who is doing the research.

Pesticides as a group have the potential to be a carcinogen, mutagen, tetratogen, fetotoxin, immunotoxin, and/or cause nervous system and organ damage. This is not an attractive list of health effects! It is also important to take into consideration the effects of toxic chemicals on children, who are smaller and whose immune systems are not as well developed, making them more vulnerable to toxic substances.

Often there is uncertainty about the direct causal links between toxic materials in the environment and human health effects because health problems

  • may be a result of multiple low levels of exposure;
  • may occur after long latency periods;
  • may be linked to the synergistic effect of several toxic materials interacting.

Because of the many uncertainties associated with the use of pesticides and other toxic substances, many citizens groups are advocating for the implementation of the precautionary principle: "When substantial evidence of any kind gives good reason to believe that an activity, technology, or substance may be harmful, we should act to prevent harm, even though knowledge is incomplete."

Climate, Weather, and Air Quality

Accelerated climate change from increased greenhouse gases is likely to cause global temperature changes and increased fluctuations in weather patterns over a time period ranging from decades to centuries. It is affected by natural changes in the environment and human activities such as burning fossil fuels and wood. Although deforestation is not a direct cause or source of increased greenhouse gases, growing trees and other plants in forests do help to buffer the effect of climate change -- as long as they are living -- through their use of carbon dioxide for growth. Possible health effects of climate change include increases in chronic respiratory and cardiovascular diseases, increases in insect-borne diseases caused by changes in precipitation and temperature, and reduced quality and the quantity of drinking water.

When a forest ecosystem is severely disturbed and changed by overharvesting, simplification, and vegetation or pest management, there will be impacts on human health. Associated activities such as road-building, truck traffic, and pulpwood processing will take their tolls on the environment, and our health. Not all forestry practices are harmful, however. It is possible to
generate a multitude of forest products over the long term without severely disturbing the forest
ecosystem and all its important functions.

Below is a short introduction to a few different forestry systems

Agroforestry combines trees and/or shrubs with agriculture, horticulture, and/or animal husbandry practices. Some techniques include the establishment of riparian buffer strips, windbreaks, alley cropping, or silvipastoral management. Agroforestry practices can be more ecologically and economically sustainable than annual monocultures because it can provide a more stable income over the long run. The integration of trees into agricultural systems has the potential to provide a greater variety of products, improve the quality of the soil, and decrease air and water pollution. Studies have shown that forested hedgerows between fields can reduce the need for pest control products by providing natural predator habitat. Forest farming, for example, is an agroforestry practice that introduces shade tolerant specialty crops into natural forest stands; these crops are then sold for ornamental, culinary or medicinal purposes. Well-known examples of specialty crops could include wild mushrooms, sugar maple, and ginseng.

Natural selection forestry is used in a woodland system where individual trees are harvested from a continually standing forest. This is an ideal system for handling mixed wood, uneven-aged forests. Highgrading is the selection of the best trees in a forest for harvest. This should be avoided in selection forestry to make sure the best trees are left as seed trees for the future improvement rather than degradation of the forest.

Highgrading is the selection of the best trees in a forest for harvest. This should be avoided in selection forestry to make sure the best trees are left as seed trees for the future improvement rather than degradation of the forest.

Clearcutting is another method of forestry where all trees are removed from a given block or forest area. After the forest is cleared, a new 'forest' is established by planting or natural regeneration. The new forest is often 'managed'-- by thinning or use of herbicides -- for one or two economically important (usually conifer) species. The purpose of this type of forest management is often to produce large amounts of softwood for pulp and paper production. It is the predominant method of forest management in Atlantic Canada. A strip cut is a narrow clearcut, offering more protection from sun and wind than larger clearcuts.

Monocultures (the use of land for growing one or two types of trees) often require the use of pesticides to 'protect' the tree crop from 'pests' and 'weeds'. Pesticides can set back pests and weeds, but also many non-target organisms such as beneficial insects, wildlife, plants, and micro-organisms. Birds, for example, help control forest 'pests'. A study in Washington State estimates that given the amount of spruce budworms eaten by evening grosbeaks, it would cost at least $1,820 per square km per year over a 100-year rotation to spray with insecticides to produce the same mortality. Even-aged, young softwood stands have a poor diversity of insects compared to older growth. In these stands, most insect species are plant eaters, while older forests have a greater abundance of predator and parasite species. Reducing bird and mammal populations that mainly eat insects can seriously affect the stand's ability to resist insect attacks.

Ecoforestry (short for ecosystem-centered economic forestry) is based on the personal connection that each practitioner develops with the forest. It can be quite similar in nature to natural selection forestry. Ecoforestry has a limitless number of possible manifestations. A few ecoforestry principles are listed below:

  1. Never cut the tallest tree. This will eventually reduce the overall height of a forest canopy, and therefore reduce the quality of lumber you are able to harvest.
  2. Any tree or part of a tree that will not be used in some way should be left in the forest. Slabwood should be returned to the forest -- perhaps to build permanent logging roads.
  3. Keep the tree as close to the stump as possible -- process and sell it locally for its most valuable use (e.g. don't sell birds-eye maple for pulp stock in Sweden. Use it for fine furniture and cabinets).
  4. Select particularly good specimens of desirable trees for seed, and never cut them down.
  5. Forest ecosystem health is always regarded as the primary product; anything extracted from the forest is a by-product.