Land UseLand Use
• 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
Forest UseForest 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.
Forest ManagementForest Management• Harvesting methods
– Selective cutting– Seed tree cutting– Strip cutting– Clear cutting
Urbanization & Urban growthUrbanization & 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.
Urbanization & Urban growthUrbanization & 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).
Urbanization & Urban GrowthUrbanization & 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
Mexico CityMexico 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
United States UrbanizationUnited 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
Urban Resources & Environmental ProblemsUrban Resources & Environmental Problems• 45% of people living in 5% of land – cities
– consume 75% of the world’s resources
• Urban areas depend upon imports
Major Urban Problems in U.S.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
Drive alone 80%
Other 4%
Public transit 5%
Car pool 11%
Motor vehicle concentrationMotor 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
Benefits of urbanizationBenefits of urbanization
• recycling more economically feasible
• decreased birth rates reduces environmental pressures
• population concentration impacts biodiversity less
Pros and Cons of Mass transitPros 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
Alternatives to Urban Land Use?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