Land Chapter 14

Land Use, Land Cover Land Use: farming, mining, building cities and highways and recreation Land Cover: what you find on a patch of land Urban: land covered mainly by buildings and roads Rural: land that contains relatively few people and large areas of open space

Where we live Before 1850 most Americans lived in rural communities Industrial revolution changed this pattern Machinery replaced people in farming and grain mill industry Better transportation People had to move to city to find jobs

The Urban-Rural Connection Whether people live in cities or countryside, people are dependent on resources produced by rural areas. Ecosystem Services: resources that are produced by natural and artificial ecosystems

Ecosystem Services Area of rural land needed to support one person depends on many factors, such as the climate, the standard of living and how efficiently resources are used. In the United States each person used the services for more than 12 hectacres

Ecosystem Services Examples Purification of air and water Preservation of soil and renewal of soil fertility Prevention of flood and drought Regulation of climate Maintenance of biodiversity Movement and cycling of nutrients Detoxification and decomposition of wastes Aesthetic beauty

Urbanization The movement of people from rural areas to cities In 1960, 70% was urban; by 1980 75%; now 81% of U.S. population is considered urban Areas that have grown slowly are usually pleasant places to live because they can handle the growth

United States Population

The Urban Crisis When cities grow too fast they often run into trouble A growing population can overwhelm the infrastructure Infrastructure: roads, sewers, railroads, bridges, canals, fire and police stations, schools, hospital, water mains and power lines When more people live in an area the living conditions deteriorate.

Urban Sprawl Rapid expansion of a city into the countryside around the city. Building of suburbs These people usually commute to work Each year in the U.S. suburbs spread over another 2.5 million acres of land

Development of Lands Marginal Lands: land poorly suited for building Examples: L.A. and Mexico City Cities were built with little room to grow, so they have to grow into surrounding mountains or slopes

Urban Planning Land-Use Planning: determining in advance how land will be used For businesses, factories, recreation, shopping and other infrastructure Many companies are required to give a detailed report of their plans, and the potential environmental impact of the project

GIS Geographic Information Systems a computerized system for storing, manipulating and viewing geographic data

Transportation Some cities were built after the invention of the car, so planning for such was not as hard Many cities have to plan for mass transit systems Save energy, reduce highway congestion, reduce air pollution and limit loss of land

Land Management & Conservation Farmlands: land used for crops and fruit. The U.S. uses almost 100 million hectacres for prime farmland These areas are often threatened by urban growth Farmland Protection Program (1996)

Land Management & Conservation Rangelands: lands that support different vegetation types but are not used for farming or timber Most common use is for livestock The current world population growth may require a 40% increase in food production of rangeland from 1977 to 2030

Rangelands Problems Most damage is done due to overgrazing (allowing more animals to graze in an area than the range can support) Results in changes in the plant community, once all the plants are gone, there is nothing to keep the soil eroding

Rangelands Maintaining the Range: Sustaining productivity means reducing overgrazing by limiting herds to sizes that do not degrade the land. Leaving the land to rest, so vegetation can grow Digging several water holes

Forest Lands Trees are harvested for a variety of products They are also important for ecosystem services, the most important removing CO2 from the atmosphere

Forest Lands Harvesting Trees On average each person used 1,800cm3 of wood per day (in the U.S. we use almost 4x that much) A 30m (~90ft) tree each year People in developing countries use trees for firewood

Forest Lands Classification of forest trees Virgin Native Tree Farms Forest that has never been cut Native Forest that is planted and managed Tree Farms Trees are planted in rows and harvested like other crops

Harvesting Trees Clear-cutting Selective cutting Removing all trees from an area of land Can cause soil erosion and destruction of wildlife habitat Selective cutting Cutting and removing only middle aged or mature trees More expensive, less destructive

Clear Cutting

Selective Cutting

Deforestation The clearing of trees from an area without replacement Due to population expansion and demands for timber Reduces wildlife habitat, causes soil erosion Rate is high in tropical rain forests Borneo deforestion

Reforestation The process by which trees are planted to re-establish trees that have been cut down in a forest land Some parts of the country require reforestation after timber has been harvested from public land 90% of all timber comes from unmanaged forests

Parks and Reserves Wilderness: an area in which the land and the ecosystems it supports are protected from all exploitation In the U.S. 32 million acres have been designated as wilderness

Benefits of Protected Areas Without protected areas many species would now be extinct Provide the only place where unspoiled forests, deserts, or prairies remain Recreation, outdoor classrooms and research laboratories

Threats to Protected Areas Litter and traffic in conservation areas Industry built close Climate change