Chapter 12 Lecture Outline* William P. Cunningham University of Minnesota Mary Ann Cunningham Vassar College *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Outline World Forests Deforestation Old Growth Harvest Methods Grasslands Parks and Preserves Terrestrial Marine

World Forests A forest is any area where trees cover more than 10% of the land. Most remaining forests are in tropical and boreal regions. Savannas - trees cover less than 20% of ground Closed canopy - tree crowns cover most of ground Highest rates of forest loss in Africa and South America

World Forests Carbon sink for carbon dioxide Moisture contributes to rainfall. Old growth forests - cover a large enough area and have been undisturbed by humans long enough that trees can live out a natural life cycle and ecological processes are normal Home to much of world’s biodiversity, endangered species and indigenous people

Forests Provide Products Wood and paper Developed countries provide less than half of industrial wood, but 80% of consumption. Paper pulp is 1/5 of all wood consumption. Fuel accounts for 1/2 of global wood use. One quarter of world’s forests are managed for wood production, much of it in single species monoculture forestry. Successful reforestation plans in China, Korea and Japan

Tropical Forests are Being Cleared Tropical forests occupy less than 10% of land surface but contain half of all species. FAO estimates that 12.3 million ha are deforested every yr, the equivalent of one football field every second.

Causes of Deforestation Logging Building roads to remove trees also allows entry to forest by farmers, miners, hunters. Conversion of forest to agriculture Accounts for 2/3 of destruction in tropics Shifting cultivation (“slash and burn”) is only sustainable if populations are small. Repeated cropping over a short time leads to permanent deforestation.

Causes of Deforestation As forests are cleared, plant transpiration and rainfall decrease. This leads to drought. Drought kills more vegetation. Fires become more numerous and extensive. More of the forest is lost.

Forest Protection Some places are being reforested (U.S. and China have had greatest gains.) About 12% of world’s forests are protected. Guanacaste National Park, Costa Rica Chipko Andolan movement in India. Women hugged trees to prevent logging and preserve firewood for their families. Debt for Nature Swaps - conservation organizations buy debt obligations, then offer to cancel the debt if the debtor country protects biologically important areas

Temperate Forests have Competing Uses U.S. Forest Service managed for “multiple uses” but many were conflicting e.g. bird watching and dirt biking. Old growth forests vs. logging Less than 10% of old growth forest remains in U.S. and 80% of that is scheduled to be logged. Spotted owl vs. logging jobs Compromise forest management plan allows some logging, but protects some prime habitat. But may not be enough to save the salmon and steelhead in northwestern rivers.

Old Growth Forest Temperate rainforest and the spotted owl. Only 2,000 remain in the old growth forests of the Pacific Northwest.

Harvest Methods Clear cutting - every tree in a given area is cut regardless of size Increases erosion and eliminates habitat Shelterwood harvesting - mature trees are removed in a series of two or more cuts Strip cutting - all the trees in a narrow corridor are harvested Selective cutting - only a small percentage of the mature trees are taken in each 10 to 20 year rotation

Harvesting Top photo shows clear cutting (removal of all trees) in Washington’s Gifford Pinchot National Forest. Bottom photo shows selective harvesting.

Logging on Public Lands? Some are calling for an end to all logging on public lands. Lands provide ecological services such as clean water, rivers for fish, irrigation, recreation. Worth $224 billion. Federal government builds roads, manages forests, fights fires and then sells the timber to logging companies for less than their costs. This is a subsidy for the logging industry. Worth $4 billion.

Logging on Public Lands? Timber companies claim logging produces jobs, supports rural communities, keeps forests healthy. Roads on public lands are another controversy. Economists argue it opens up land for motorized recreation and industrial uses. Wildlife supporters see it as disruptive. Clinton protected 23.7 million ha of wilderness from roads; Bush overturned this and ordered expedited logging and mining.