Forest Resources
Forestry
• Forestry is the science and art of cultivating,
maintaining, and developing forests and their
resources.
• The forests cover almost 1/3 of Earth’s land
surface.
• Forests were primarily used for fuel and food
(subsistence).
• Currently, forests are used by the commercial
Forestry
• Two Types of Forest Include:
1. Broadleaf Forest (Deciduous)
• Forests with fleshy, leaved trees that occur in moist regions (E.g., Oak Trees, Birch Trees). Lose their leaves for the winter season.
2. Coniferous Forest (Needleleaf)
Forestry
Forest Harvesting
• Two Types of Harvesting Approaches:• 1. Clear-cutting: The process of harvesting all timber in an area at the same time. A form of clear-cutting is strip-cutting.
• More yield. (Good!)
• No habitat for animals. (Bad!)
• Safer for workers involved. (Good!) • Less expensive. (Good!)
Clear-cutting
Advantages
• This method is cheap to use.
• Uses less resources (e.g. less fuel for machinery).
• Fast harvesting. • Less dangerous
method for workers.
Disadvantages
• Soil erosion increases because of increase in soil exposure.
• Damages the forest and undergrowth
vegetation.
• Biodiversity is decreased.
Clear-cutting
Strip-cutting (i.e. a form of clear-cutting):
• This method consists of cutting rows of trees and leaving rows of trees between the cut rows.
• This method of clear-cutting is more environmentally friendly.
• Soil is not exposed (at least beneath the uncut rows).
• Leaves forest for animals to live in (i.e. in the uncut rows). Strips are left connected sometimes for
Forest Harvesting
• Two Types of Harvesting Approaches:
• 2. Selective Cutting: Occurs when only selected trees are harvested from a forest site. For
example, cutting only mature trees of a specific kind.
• Less yield. (Bad!) • Less safe. (Bad!)
• More expensive. (Bad!)
Selective Cutting
Advantages
• Most of the forest is left intact.
• Biodiversity is not harmed.
• Young trees are left to grow and replace mature trees.
• Soil erosion does not increase due to it
being preserved under the uncut rows of
trees.
Disadvantages
• Costs more.
• Hard not to damage other trees.
• Yields are lower.
See Figure 10.4 In Textbook
Reading Case Studies
• Consider:
1. If clear-cutting or selective cutting is used.
2. If the operation is labour-intensive or capital-intensive. 3. The uses of the harvested timber.
4. The market for the harvested timber.
5. Factors that are difficult for the owner of the operation to overcome.
6. The forest management practices that the owner of the operation engages in.
• Read and discuss the case study entitled, “Tree
Other Uses
• Forests could be used for medical research (e.g. The
Canadian Yew) and for tourism (or recreational
purposes).
• http://environment.about.com/od/healthenvironment/
a/rainforest_drug.htm Tropical Rain Forests!
• Consider old-growth forests and their values.
Threats to Forest Resources
1) Deforestation:
• The conversion of forested land into another use.
• E.g., farms, cities.
• Tropical rainforests experience most of the world deforestation. Some rainforests are expected to vanish within the next 50 years.
2. Climate Change:
• Warmer temperatures cause:
Trends
• Global population of humans is increasing exponentially and so is the demand for food.
• Therefore, more and more
deforestation is occurring for the
purpose of obtaining more and more
Read and Discuss
• Read about “The Main River Old-growth
Forest” in Newfoundland.
• Read the case study, entitled “Logging the
Main River Watershed”.
• Consider:
• The problem.
• The positions taken by each side.
• The reasons for each side’s positions.
Sustainable Forestry
Sustainable Forestry:
• Methods followed to protect the world’s forests for years to come.
Some practices include:
• Selective cutting
• Using slash roads (i.e. roads covered with branches for the purpose of protecting undergrowth vegetation and soil).
• Tree planting
• Controlled burns (i.e. for the purpose of maintaining soil fertility and for eliminating forest pests).
• Pest management
• If we look at sustainable forestry from a “systems model” perspective, we can see that we have three options:
1. Improve what we input into forestry (e.g., replanting trees, adding seedlings) OR
2. Improve processes, as examples, road construction, harvesting techniques, environmental protection
actions, and reducing losses (e.g. use all of the trees for different purposes) OR
Forest Cover
Continents
• North America • South America • Europe
• Africa • Asia
• Australia
% Forest Cover
• 32.2 % • 51.8 % • 33.4 % • 23.2 % • 20.2 % • 23.5 %
Forest Depletion
• Earth's forests are vanishing at 150,000 km2 per year.
• Tropical rainforests suffer 140,000 km2 of the above total.
Causes (and percentages) of Forest Depletion
• 55 % caused by slash and burn cultivation. • 20 % caused by logging.
