Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Forestry.

Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

Forestry


Outline

• World Forests

• Tropical Forests Swidden Agriculture

• Temperate Forests Harvest Methods Fire Management


WORLD LAND USES

• Earth’s total land area is about 29% of globe. 11% of landmass is now used for crop

production.

Half of present forests and grazing lands could be converted.

- Immediate and destructive impacts on landscape and wildlife.


Uses of Landmass (29% of world)


WORLD FORESTS

• Forests play vital ecological roles Regulating climate, controlling water

runoff, providing food and shelter for wildlife, and purifying air.

• Provide valuable materials. Wood, paper-pulp.

• Scenic, cultural, and historic value.


Forest Distribution

• 1/3rd of original forests and woodlands have been converted to other uses. Forests and woodlands cover 32% of

earth’s land surface.

Greatest concern is over protection of Old-Growth Forests.

Only 22% retain old-growth characteristics.


World Forests


Forest Products

• Wood plays a part in more activities of the modern economy than any other commodity.

Industrial Timber and unprocessed logs account for about half of worldwide wood consumption.

- Developed countries produce less than 1/2 all industrial wood, but account for 80% of consumption.


Forest Products

• US, Russia, and Canada are largest producers of industrial wood and paper pulp. Japan is world’s largest wood importer.

- US is both major exporter and importer. Buy wood and paper from Canada

and processed wood products from Japan.

Sell raw logs to Japan and other countries.


Forest Management

• Approximately 25% of world’s forests are actively managed for wood production. Sustainable harvest is key to regeneration.

- Most countries replant far fewer trees than were harvested.

Many reforestation projects involve Monoculture Cropping.

Disrupts ecological processes.


TROPICAL FORESTS

• Occupy 10% of landmass, and contain:

More than 2/3rds of all higher plant biomass.

At least 1/2 of all plant, animal, and microbial species.


Tropical Forests Shrinking

• 0.8% of remaining forest cleared each year.

- Countries have economic and political reasons to hide extent of losses.

Brazil has largest rainforests, and highest rate of deforestation.


Tropical Forests Shrinking


Deforestation inthe Amazon Basin

LoggingLogging

Cattle grazingCattle grazing


Tropical Forest Losses


Amazon Deforestation Remains High

Even selective logging destroys canopy,causes river siltation, opens roads


Desertification threatens forest edges


Chipko Movement in India

Women blockingWomen blockingmass logging,mass logging,deforestationdeforestation


Swidden Agriculture

• Can be ecologically sound and sustainable if performed carefully and in moderation.

• Slash and Burn Small lot cleared, dried, and burned.

- Ashes used to prepare seedbed. Fast-growing crops planted to control

erosion, shade crops, and anchor soil.


Cropped intensively for 1-2 years,

and then rested 10-15 years.


Logging and Land Invasions

• Other major source of forest destruction

Bulldozed roads make it possible for people to move into the forest for farmland.

- Forest clearing leads to river degradation through increased silt and sediment flow.


Debt-for-Nature Swaps

• Banks, governments, and lending institutions hold nearly $1 trillion in loans to developing countries.

Conservation organizations buy debt obligations discount, and then offer to cancel the debt if the debtor country will agree to protect or restore an area of biological importance.


TEMPERATE FORESTS

• Northern countries have a long history of liquidating forest resources. Siberia contains 1/4 of the world’s timber

reserves.- Asian companies cutting 10 mil. acres/year


Temperate Forests in the U.S.


Ancient Forests of the Pacific Northwest

• Redwoods can reach 3-4 m in diameter, 90 m in height and 1,000 years in age. Temperate rainforests are 2nd only to

tropical rainforests in biodiversity.- Accumulate more biomass in standing

vegetation per unit area. Less than 10% of virgin temperate

rainforest remain (80% scheduled to be cut).


Wilderness and Wildlife Protection

• Forest products industry employs about 150,000 people in the Pacific NW

• Adds nearly $7 billion annually to the economy.

• Recreation has 16x jobs.


Spotted Owl controversy

1989 environmentalists sued USFS over plans to clear-cut remaining old-growth forests,

Argued spotted owls were endangered and must be protected.



- Timber industry claims 40,000 jobs lost. Environmentalists dispute number.

Other reasons Mechanization Clear-cutting Export of logs to Japan


Harvest Methods

• Clear-Cutting - Every tree in a given area is cut regardless of size. Fast and efficient, but wastes small trees,

increases erosion, and eliminates wildlife habitat.

Coppicing - Encourage stump-sprouts. Seed-Tree - Leave few mature trees. Shelterwood - Remove in series of cuts.


Harvest Methods

• Strip Cutting - Harvesting all trees in a narrow corridor.

• Selective Cutting - A small percentage of mature trees are taken in 10-20 year rotation. Can retain many characteristics of mature,

old-growth forests.


Menominee Sustainable Forestry


Below-Cost Salvage Sales

• USFS has historically regarded its primary job as providing a steady supply of cheap logs to the nation’s timber industry. Often, timber prices have not been enough

to repay management costs.- Hidden subsidy to timber industry.

USFS builds roads in order for timber companies to extract trees.


FIRE


Fires caused by poor logging practices

Wisconsin, 1871:Deadliest forestfire in recorded

world history kills1,200-1,500


Southeast AsianRainforest Fires, 1997

Palm oil plantations


Mexico/Central AmericaRainforest Fires, 1998

Cover for illegal logging


Brazilian AmazonRainforest Fires, 1999

Land-hungry farmers


Fire Management

• Recent studies show fire plays an important role in many forested ecosystems.

Eliminating fire has allowed shrubs and small trees to fill some forest floors.

- As woody debris accumulates, chances of a major fire increase.

Often, attempts to stop fires cause more ecological damage than the actual fires.


Fire Suppression:Wisconsin River Bluffs at Sauk City, 1870s-1990s


Fire Management

• For 30 years, the NPS has followed a policy of allowing some natural fires to burn, and even setting some prescribed fires. But after 70 years of fire suppression, fuel has

now built up to a point where fires can easily escape “control.”

- The dilemma is how to remove excess fuel while protecting property, human life, and forest ecosystems.


Yellowstone Fires, 1988

Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Forestry.

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