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 Parts1. Canopy -- TOP2. Understory -- Bottom3. 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 SPRUCEEx: 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.

Spruce Bud-worm -- Larva eats needles of SPRUCE, which gives the trees a sickly look, eventually causing the tree to die.

North America

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 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!!

Fire

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.