Land Use

Land 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 http://planning.maryland.gov/OurWork/landUseIMap.shtml

Forest Use More than ½ converted to cropland, pasture, settlements, and wasteland Ecological roles? Used for: ~25% of world’s forests are actively managed for wood production. Ecological roles? Regulating climate, controlling water runoff, providing food and shelter for wildlife, and purifying air. Used for: Fuel, construction materials, paper products

Forest Management Harvesting methods Selective cutting Seed tree cutting Strip cutting Clear cutting http://www.hippocampus.org/course_locator?course=AP%20Environmental%20Science&lesson=74&topic=1&width=800&height=684&topicTitle=Tree%20Harvesting&skinPath=http://www.hippocampus.org/hippocampus.skins/default

Urbanization & Urban growth Urban area-contains more than 1000 people per square mile Urban growth due to: natural increase - births immigration Trends of urban growth: ~75% of people in developed countries live in urban areas 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. - poor are pulled to urban areas or are pushed from rural areas

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 (35.7 mil), Mexico City (18 mil), New York (19 mil). http://news.yahoo.com/photos/hong-kong-vertigo-photographer-captures-the-urban-grid-slideshow/

Urbanization & Urban Growth Developing countries-most will be urban growth 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 City Tied for 2nd largest city with 19 million people (1 in 5 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 1/3 (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

Urban Resources & Environmental Problems 50% of people living in 5% of land – cities – consume 75% of the world’s resources Urban areas depend upon imports

Urban Resource and Environmental Problems Destruction of plant life - what is $ value? Cities produce little of own food Urban heat island effect --> dust dome Water supply and flooding problems High pollution exposure

Urban Resource & Environmental Problems Excessive noise exposure  health effects Hearing loss, hypertension, muscle tension, migraines, headaches, higher cholesterol levels, gastric ulcers, irritability, insomnia, psychological disorders, aggression

Benefits of urbanization recycling more economically feasible decreased birth rates reduces environmental pressures population concentration impacts biodiversity less

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. Main causes: Automobiles and highway construction Living costs Urban blight (positive feedback) Government policies Highway Trust Fund Living costs cheaper Urban blight: cities forced to reduce services, raise tax rates, or both; crime rates increase; infrastructure deteriorates Government policies: funded by federal gasoline tax, pays for construction and maintenance of roads and highways

Impacts of Urban Sprawl Fig. 25-8 p. 666

Impacts of Urban Sprawl

Motor vehicle concentration Ground transportation: individual (cars, etc) and mass (buses and rail) Drive alone 80% Other 4% Public transit 5% Car pool 11%

Pros and Cons of Mass transit 3% mass transit use in U.S. to 47% in Japan 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

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 Mixed land uses Create a range of housing opportunities and choices Create walkable neighborhoods Encourage community and stakeholder collaboration in development decisions Take advantage of compact building design Foster distinctive, attractive communities with a strong sense of place Preserve open space, farmland, natural beauty, and critical environmental areas Provide a variety of transportation choices Strengthen and direct development toward existing communities Make development decisions predictable, fair, cost effective (no cookie cutters)