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GEOG 4400: Resource Use. Lecture 7 Biota. “Any fool can destroy trees. They cannot defend themselves or run away.” John Muir. The World’s Forests. Where How much. Where. How much Change. Change. Deforestation. 10.1 billion acres of forest in the world (31% of land cover)
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GEOG 4400: Resource Use Lecture 7 Biota
“Any fool can destroy trees. They cannot defend themselves or run away.” John Muir
The World’s Forests • Where • How much
Where • How much • Change
Deforestation • 10.1 billion acres of forest in the world (31% of land cover) • 50% of tropical forests cleared (2/3 in SE Asia) • 40-50 million acres per year • 150 acres per minute • Football field per second
Deforestation • agriculture • local needs • export crops • wood supply • fuelwood
Causes of Deforestation • Poverty • Fuelwood crisis
Causes of change • Population growth • Capitalism • Inappropriate technology • Inappropriate government policies • Forest concessions • Underpricing • Removal of indigenous population • Ecological collapse • Tragedy of the commons
Forest resources • Hardwood • Coffee • Spices • Nuts • Cacao (chocolate) • Latex • Dye • Medicines • Agriculture (rice, wheat, corn) • 50-90% of all biological diversity is in forests • Potential loss of 5-15% of world’s species from 1990-2000 • 50-150 species per day
Uses of forest products • Traditional • Industrial • Services
Types of harvest • Shelterwood • Selective • Clear-cutting • Biomass harvesting
Effects of harvesting • Roads (340,000 miles = 10x interstate highway system) • Compaction from heavy equipment • Erosion • Nutrient removal • Water regime alteration • Stream conversion
Trends in forestry • Industrial wood supply • Plantations • Global trade • Fuelwood • Services
Other problems: • Greenhouse effect
Forest structure • Fire • Good: release nutrients, remove old sick trees, allow light, burn off fuel • Bad: consume biomass, increase in runoff, sedimentation • Fire frequency- return interval • Types: ground, surface, crown, firestorm • Disease: fusiform rust, dwarf mistletoe, root diseases • Insects: spruce budworm, gypsy moth, pine beetle
Reforestation • Causes of change • Population growth • Capitalism • Inappropriate technology • Inappropriate government policies • Forest concessions • Underpricing • Removal of indigenous population • Ecological collapse • Tragedy of the commons
Reforestation • Natural regeneration/ seed tree • Artificial seeding • Seedling plantings • Plantation conversion (forest??)
Sustained Yield • Harvesting of a species at a rate equal to its reproduction or maturation
Multiple Use Sustained Yield Act of 1960 • recognize other uses of national forests • balanced management approach • timber • watershed maintenance • wildlife habitat • recreation
National Forest Management Act of 1976 • limited size of clearcuts • protect riparian areas • regulation of rate of harvest • wilderness reviews (RARE studies)
