Transcript Forests Notes - GEOCITIES.ws

Chapter 10: Forest and Mineral Resources
Note: WE ARE NOT COVERING MINERAL RESOURCES
Forests
• cover a third of the earth’s land surface
• forests reflect unique environmental conditions
• Ex: equatorial regions: evergreen broadleaf trees
• northern regions: evergreen conifer trees
• temperate regions: deciduous broadleaf trees
Tropical Rainforests
Two Major Parts
1. Canopy -- TOP
2. Understory -- Bottom
3. Litter Layer
Butresses
World’s Rainforests
Major Issues in The Tropical Rainforest
1.
Deforestation -- Slash and Burn Agriculture
-- Human housing, lumber
-- losing plants, bio-mass
2.
Extinction of plants and animals
Boreal Forest
Canopy -- TOP
Under-story -- Bottom
Litter Layer
Worlds Boreal Forest
1.3 Billion Acres
Pure Stands: when a single species dominates an area
Ex: Needle leaf forests : dominated by FIR or SPRUCE
Ex: Broadleaf forests: dominated by MAPLE, BIRCH, etc
Deforestation
• conversion of forested land for other uses
• most severe threat to forest resources
WHY do we deforest??
• for agricultural purposes
• other resources like mining, hydro developments.
• For living space
Tree Harvesting
3 major ways
1. Clear-Cutting
2. Strip Cutting
3. Selective Cutting
1. Clear-Cutting
From This...
To This
Clear-cutting: harvesting all the timber in an area at the
same time
Advantages
• rapid, economical and least dangerous method
• re-vegetation programs exist
•good for tourism -- clear-cuts are good for moose hunting
Clear-cutting
Disadvantages
• looks ugly
•high erosion
•loss of wildlife and plant habitat
•physically tough of the ecosystem
Strip Cutting
-- strips of forest, 20 to 100 meters wide are clear-cut
Strip Cutting
Advantages
• less ecological disruptive
•less erosion
•less negative effects on wildlife
Strip Cutting
Disadvantages
• strip cutting requires more forest space to get the same yields
•more forests areas = more forest roads = increased runoff
Selective Cutting
When selected trees are harvested from a forest site
Advantages
• allows smaller trees grow to market size
• far less ecologically disruptive, better for wildlife
• allows for more recreational uses
Selective Cutting
Disadvantages
• expensive
•lower yields
•workers have to be careful not to damage un-harvested trees
•maintenance of forestry access roads
Forestry Issues in the world.
1. Insects
2. Animals
3. Fire
Insects and Forestry.
North America
Spruce Bud-worm -- Larva eats needles of SPRUCE, which
gives the trees a sickly look, eventually causing the tree to
die.
Wildlife.
Moose -- Alces alces -- eater of twigs
Moose browse on Spruce and Fir, but
mainly fir
Fir is a primary resource required for both
paper and the lumber industries.
Several moose in an area can decimate a
pure stand of trees.
Canada, Russia,
Poland, USA
Fire
•Fire can also damage the forest
•When a fire burns down trees it not only
effects the forestry industry but also the
overall health of the ecosystem.
•Lost timber = no paycheck!!
BUT…
Fires are needed
in some areas to
help replenish
the species
affected.
Eg: Spruce and
Pine need fires
Heat from fires releases
seeds into the environment.
Sustainability and Forestry.
Sustainable Forestry: providing for the existence of ;or
maintenance of a forest resource.
In other words, making sure that there is something left
for the future through various strategies
“We do not inherit the earth from our parents, we
borrow it from our children”
Aldo Leopold
Sand County Almanac
How do were manage our forests in a sustainable
way??
• reforest harvested areas with appropriate species
• protect water quality and prevent erosion
•Conserve fish and wildlife habitat
• Maintain and enhance species biodiversity.
• Are sensitive to the aesthetics of harvesting
• protect important cultural, historical, and ecological
sites.
•Improve utilization and reduce waste.