颏敎污-LandUseintheWorld.pptVIP

Land Use in the World Land Use in the United States U.S. Public Lands Managing U.S. Public Lands Changing Management Changing Management Changing Management Changing Management Today’s Management Conflicting Demands Wilderness Problems Park Problems Managing and Sustaining National Parks Forest Problems Types of Forests Rangeland Problems The Fuelwood Crisis Degradation of Tropical Forests Logging Roads Tropical Deforestation Reducing Tropical Deforestation * Rangeland and pasture 29% Management ethics Economic Balanced multiple use Ecological Preservationist Through late-1800s: economic Developed to maximize use and profit Sold to homesteaders, railroads, timber and mining companies Late-1800s: balanced multiple use Use in several ways, but manage properly so resource is not damaged Maximum sustained yield Set aside forest reserves to ensure adequate timber supply, protect river watersheds Also late-1800s: ecological Use it, but emphasize maintaining natural aspects (plants, animals) 1872: lands set aside for eventual 1st national park - Yellowstone Ethic supported greatly by U.S. President Theodore Roosevelt Throughout 1900s: preservationist No development, leave as is for future Aldo Leopold, WI conservationist 1964: National Wilderness Act (4%) - lands set aside, retained in natural state, no development unless for the “national good” Most lands managed according to balanced multiple use or ecological ethics - e.g. U.S. Forest Service Bureau of Land Management Public lands still facing many problems Mineral Resources Suffering from overuse Limited entry in many areas Timber, mining companies want access to resources For the “national good” Severe overuse Billions of visitors each year Cars, noise, pollution, litter, crime Conflicts between providing for visitor enjoyment and still conserving resources Most parks are too small to maintain biodiversity Invasion by exotic species Popularity a major problem Traffic jams and air pollution