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Published byPierce Ross Modified over 9 years ago
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Land Use
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29% of the earth is land –29% forests and woodlands –27% range and pastures –11% cropland –33% tundra, marsh, desert, urban areas, bare rock, ice or snow
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Forest Use More than ½ converted to cropland, pasture, settlements, and wasteland Ecological roles: –Regulating climate, controlling water runoff, providing food and shelter for wildlife, and purifying air. Used for: –Fuel, construction materials, paper products Approximately 25% of world’s forests are actively managed for wood production.
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Forest Management Harvesting methods –Selective cutting –Seed tree cutting –Strip cutting –Clear cutting
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Urbanization & Urban growth Degree of urbanization is percentage of population living in area of greater than 2,500 people Urban growth due to: –natural increase - births –immigration - poor are pulled to urban areas or are pushed from rural areas Trends of urban growth: –Increase of 2% to 45% of people in urban areas since 1950 –By 2050 about 66% of the world’s people will be living in urban areas.
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Urbanization & Urban growth The number of large cities is mushrooming –megacities and megalopolis –Today, more than 400 cities have over 1 mil. or more people. 19 megacities with over 10 mil. people i.e.Tokyo (28 mil), Mexico City (18 mil), New York (17 mil).
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Urbanization & Urban Growth Most of growth in developing countries will be urban growth with all of its problems –38% of the people in live in cities. –By 2025 it will be 54%. Poverty is becoming increasingly urbanized –slums, squatter settlements and shantytowns –at least 1 billion people live in crowed slums of inner cities. –No access to water, sewer, electricity, education etc. 100 mil people are homeless & sleep on the streets Case study - Mexico City
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Mexico City The world’s second largest city with 18 million people or one in five Mexicans –severe air pollution (over 4 million cars) within a valley that causes an estimated 100,000 premature deaths/year –high unemployment rate, close to 50% –high crime rate –over one-third (6 million) of its residents live in slums (barrios) without running water, sewer (but running sewage), or electricity –high infection rates i.e. salmonella, hepatitis
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United States Urbanization Migration to large central cities Migration from cities to suburbs Migration from north & east to south & west Urban sprawl, growth of low-density development on the edge of cities. Encouraged by: - availability of cheap land, (forests, agriculture fields etc.). - government loans guarantees for new single-family homes - government & state funding of highways - low-cost gasoline encourage car use - low interest mortgage
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Impacts of Urban Sprawl Fig. 25-8 p. 666 Fig. 25-8 p. 666
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Impacts of Urban Sprawl
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Urban Resources & Environmental Problems 45% of people living in 5% of land – cities – consume 75% of the world’s resources Urban areas depend upon imports
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Major Urban Problems in U.S. Deteriorating services Aging infrastructures Budget crunches from lost tax revenues as businesses and affluent people leave Rising poverty with violence, drugs, decay
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Drive alone 80% Other 4% Public transit 5% Car pool 11% Motor vehicle concentration Ground transportation: individual (cars, etc) and mass (buses and rail) Motor scooters - effort to change to electric Riding bicycles; less pollution and dangerous and more efficient than walking –bicycles available for public use –bike and ride systems
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Benefits of urbanization recycling more economically feasible decreased birth rates reduces environmental pressures population concentration impacts biodiversity less
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Pros and Cons of Mass transit 3% mass transit use in U.S. to 47% in Japan 20% gasoline tax revenues to mass transit Rapid rail, suburban trains and trolley - efficient at high population density High speed rail lines – replace planes, buses and private cars; but require large government subsidies Bus systems more flexible than rail systems but efficient when full
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Alternatives to Urban Land Use? Smart Growth-efficient use of land resources and existing urban infrastructure –Using zoning laws to prevent sprawl, direct growth in certain areas Make downtown vital and livable Alleviate substandard housing Solve pollution problems Efficient mass transportation Provide ample green space
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So What Does This Mean? We need to plan, plan, and do more planning…. And that’s what you’ll be doing….. Good luck!
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