Environmental Science Chapter 14

“Land”

1

Section 1: How We Use Land

2

Land Use and Land CoverUrban Land:

• Land that is covered mainly with buildings, homes, industry, and roads (6 % of US land)

• Area that contains 2,500 or more people and usually has a governing body

Rural Land:

• Land that contains relatively few people and large open space

3

Land Use and Land CoverRangeland:• Land used to graze livestock

and wildlife• 26% of US land

Forestland:• Land used for harvesting wood,

wildlife, fish, nuts, and other resources (Oconee, Ga)

• 28 % of US land

4

Land Use and Land CoverCropland: Parks and Reserves:

• Land used for recreation and scenic enjoyment and for preserving native animal and plant communities.

• 13 % of US land

• Land used to grow plants for food and fiber.

• 20 % of US land

5

Where We Live• Until 1850 – most people lived in rural areas. They were

dependant on the land for crops and livestock (food /clothes).• The Industrial Revolution changed this drastically. Cars and

machinery meant you didn’t have to live where food/goods were produced.

• People are still dependent on the resources produced in rural areas: clean drinking water, fertile soil, land for crops, trees

6

The Urban-Rural Connection• The resources that are produced by natural and artificial

ecosystems are called 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

7

Supporting Urban Areas• Rural land needed to support 1 person depends on many factors:

*Climate *Standard of living *How efficiently resources are used

Ecosystem Services per person: o (Earth total: 12.4 billion hectares)o Most developed countries:

about 8 hectares of land and watero US: 12 hectareso Germany: 6 hectares

8

Section 2: Urban Land Use

9

Urbanization: Urban Sprawl:• The movement of people from

rural areas to cities.• Usually for more jobs/better

pay.• In 1960 - 70 % of US – urban• By 1980 – only increased to

75 %.

• Rapid expansion of a city into the countryside around a city.

• Usually built on land previously used for food production

• In 2000 – more Americans lived in suburbs than in cities and countryside combined

10

Infrastructure: Urban Crisis:• All the things society builds for

public use.• Include: railroads, sewers,

roads, bridges, canals, fire and police stations, schools, hospitals, power lines, water mains.

• When more people live in a city than its infrastructure can support.

• Living conditions deteriorate. • Developed countries can

suffer from urban sprawl.• Ex – Japan

11

Land-use Planning: Geographic information system (GIS):

• Is determining in advance how land will be used:

• Ex: where houses, businesses, and factories will be built, also where land will be protected for recreation.

• Computerized system for storing, manipulating, and viewing geographic data.

• GIS software allows a user to enter different types of data about an area.

• Such as: location of sewer, roads, and parks, and then create maps.

12

Section 3: Land Management and Conservation

13

Farmland:• Is land that is used

to grow crops and fruit.

• Provides an important oxygen source for urban areas.

• Moderates the temperature of urban areas.

14

Rangelands: Overgrazing:• Land that supports different

vegetation types like grasslands, shrublands, and deserts.

• Is not used for farming or timber production.

• Allowing more animals to graze in an area than the range can support.

• Too many of the plants are eaten and the land becomes degraded.

15

Maintaining the RangeTo sustain the productivity

of rangeland:1) Reduce overgrazing by

limiting the herds to sizes that do not degrade the land.

2) Leave the land unused for periods of time so that the vegetation can recover.

3) Use methods such as killing invasive plants, planting native vegetation, and fencing areas to let them recover .

16

Forest Land Harvesting trees:• People use enormous amounts of

wood.• Worldwide average: 1,800 cm3 of

wood per person per day.• US: uses 3.5 times this amount• About 1.5 billion people in

developing countries depend on firewood as their main source of fuel.

• Clearcutting: the process of removing all the trees from an area of land.

17

Deforestation: Reforestation:• The clearing of trees from an

area without replacing them.Consequences:• reduction of wildlife habitat• soil erosion (no tree roots to

hold the soil in place)• loss of topsoil

• The process by which trees are planted to re-establish trees that have been cut down in a forest land.

• In some places - is happening at a faster rate than trees are being cut down.

• Ex. New England – now contains more forest than it did a century ago.

18

Parks and Preserves: Wilderness:• Established in 1870s• After explorers brought news

to congress of magnificent land in Wyoming and Montana.

• This became the first national park: Yellowstone

• Today - the US has about 50 national parks.

• An area in which the land and the ecosystems it supports are protected from all exploitation.

• So far, 474 regions covering almost 32 million acres have been designated as wilderness in US.

• Open to hiking, fishing, boating (w/out motors), and camping.

19

Threats to Protected Areas: Conservation Corridor:• Litter• Traffic jams• Rangelands, mining and

logging sites, oil and gas drilling operations, factories, power plants and urban areas are close enough to affect parks.

• Strips of protected land that connect one preserve to another preserve.

20