Chapter 18 Land Resources

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Chapter 18Land Resources
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Overview of Chapter 18

• Land Use
• World land use
• US land use
• Wilderness Park and Wildlife Refuges
• National Parks
• Wildlife Refuge
• Forests
• Forest management
• Deforestation
• Rangeland and Agricultural Land
• Wetlands and Coastal Areas
• Conservation of Land Resources

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HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITY

• We have depleted and degraded some of the earths
  biodiversity and these threats are expected to
  increase.

Figure 10-2
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Land Use- Worldwide
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Land Use- United States
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Forest Trends in US

• Most temperature forest are steady or expanding
• Returning stands lack biodiversity of original
  forests
• More than half of US forest are privately owned
  (right)
• Forest Legacy Program
• Conservation easement

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Managing Public and Private Land

• Public Planning and Land Use
• Land use decisions are complex and have multiple
  effects
• Must take into account all repercussions of
  proposed land use
• Management of Federal Land
• Wide-Use Movement
• Environmental Movement

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Wilderness Parks and Wildlife Refuges

• Wilderness
• A protected area of land in which no human
  development is permitted
• Wilderness Act (1964)
• Set aside federally owned land as part of
  National Wilderness Preservation System
• No development permitted (including roads)
• Managed by NPS, USFS, FWS BLM

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Wilderness

• Some areas have a limited number of permitted
  human guests to reduce impact
• Other problems include invasive species

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National Park System
Yosemite National Park

• Created in 1916
• Currently includes 58 parks
• Primary goal
• Teach people about the natural environment,
  management of natural resources and history of a
  site

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National Park System

• Threats to U.S. Parks
• Crime Vandalism
• Traffic jams
• Pollution of the soil, water and air
• Originating both inside and outside the park
• Resource violations
• Natural Regulation
• Policy to let nature take it course
• No culling wildlife
• No suppressing wildfire

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Wildlife Refuges

• National Wildlife Refuge System (1903)
• Represent all major ecosystems founds in the US
• Mission
• To preserve lands and waters for the conservation
  of fishes, wildlife and plants of the US
• Recreation (including hunting and fishing) are
  permitted
• Cannot impede conservation efforts

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Forests

• Role in Hydrologic Cycle (right)
• Forest Management
• Deforestation
• Forest Trends in the US
• Trends in Tropical Forests
• Boreal Forests

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MANAGING AND SUSTAINING FORESTS

• Forests provide a number of ecological and
  economic services that researchers have attempted
  to estimate their total monetary value.

Figure 10-4
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Types of Forests

• Old-growth forest uncut or regenerated forest
  that has not been seriously disturbed for several
  hundred years.
• 22 of worlds forest.
• Hosts many species with specialized niches.

Figure 10-5
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Types of Forests

• Second-growth forest a stand of trees resulting
  from natural secondary succession.
• Tree plantation planted stands of a particular
  tree species.

Figure 10-6
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Forest Management

• Traditional Forest Management
• Low diversity- monocultures (right)
• Managed for timber production
• Ecological Sustainable Forest Management
• Environmentally balanced
• Diverse trees
• Prevent soil erosion
• Preserve watersheds
• Wildlife corridors- unlogged

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Harvesting Trees

• Building roads into previously inaccessible
  forests paves the way for fragmentation,
  destruction, and degradation.

Figure 10-8
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Harvesting Trees
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Harvesting Trees - Clearcutting
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Harvesting Trees
Effects of clear-cutting in the state of
Washington, U.S.
Figures 10-10 and 10-11
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Deforestation

• Temporary or permanent clearance of large
  expanses of forest for agriculture or other use
• World forests shrank 90 million acres from
  20002005
• Causes
• Fire
• Expansion of agriculture
• Construction of roads
• Tree harvest
• Insect and disease

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Global Outlook Extent of Deforestation

• Human activities have reduced the earths forest
  cover by as much as half.
• Losses are concentrated in developing countries.

Figure 10-7
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Solutions

• We can use forests more sustainably by
  emphasizing
• Economic value of ecological services.
• Harvesting trees no faster than they are
  replenished.
• Protecting old-growth and vulnerable areas.

Figure 10-12
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Types and Effects of Forest Fires

• Depending on their intensity, fires can benefit
  or harm forests.
• Burn away flammable ground material.
• Release valuable mineral nutrients.

Figure 10-13
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Solutions Controversy Over Fire Management

• To reduce fire damage
• Set controlled surface fires.
• Allow fires to burn on public lands if they dont
  threaten life and property.
• Clear small areas around property subject to fire.

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Solutions Controversy Over Fire Management

• In 2003, U.S. Congress passed the Healthy Forest
  Restoration Act
• Allows timber companies to cut medium and large
  trees in 71 of the national forests.
• In return, must clear away smaller, more
  fire-prone trees and underbrush.
• Some forest scientists believe this could
  increase severe fires by removing fire resistant
  trees and leaving highly flammable slash.

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How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Do you support repealing or modifying the Healthy
  Forests Restoration Act of 2003?
• a. Yes. Local officials and scientists are
  probably most qualified to manage their local
  forests.
• b. No. The initiative favors the timber companies
  rather than effectively protecting and managing
  the forests.

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US National Forests

• Managed for multiple uses
• Timber harvest
• Livestock forage
• Water resource and watershed protection
• Mining, hunting, fishing, etc.
• Road building is an issue
• Provides logging companies with access to forest
• Clearcutting is an issue

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CASE STUDY FOREST RESOURCES AND MANAGEMENT IN
THE U.S.

• U.S. forests cover more area than in 1920.
• Since the 1960s, an increasing area of old
  growth and diverse second-growth forests have
  been clear-cut.
• Often replace with tree farms.
• Decreases biodiversity.
• Disrupts ecosystem processes.

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Controversy over Logging in U.S. National Forests

• There has been an ongoing debate over whether
  U.S. national forests should be primarily for
• Timber.
• Ecological services.
• Recreation.
• Mix of these uses.

Figure 10-14
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Case-In-Point Tongass National Park

• One of worlds few temperate rainforests
• Prime logging area
• Modified 1997 Forest Plan
• Roadless Area Conservation Rule (2000)
• Politics rules government agencies

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Trends in Tropical Forests

• Tropical rainforests (below) and tropical dry
  forests

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Disappearing Tropical Rain Forests

• Population growth
• Cannot account for all of it
• Immediate causes
• Subsistence agriculture
• Commercial logging
• Cattle ranching
• Other causes
• Mining
• Hydroelectric power

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Why Should We Care about the Loss of Tropical
Forests?

• About 2,100 of the 3,000 plants identified by the
  National Cancer Institute as sources of
  cancer-fighting chemicals come from tropical
  forests.

Figure 10-18
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Causes of Tropical Deforestation and Degradation

• Tropical deforestation results from a number of
  interconnected primary and secondary causes.

Figure 10-19
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Solutions
Sustaining Tropical Forests
Restoration
Prevention
Protect most diverse and endangered
areas Educate settlers about sustainable
agriculture and forestry Phase out subsidies
that encourage unsustainable forest use Add
subsidies that encourage sustainable forest
use Protect forests with debt-for-nature swaps
and conservation easements Certify sustainably
grown timber Reduce illegal cutting Reduce
poverty Slow population growth
Reforestation Rehabilitation of degraded
areas Concentrate farming and ranching on
already-cleared areas
Fig. 10-20, p. 207
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Disappearing Tropical Dry Forests

• Primarily destroyed for fuelwood
• Used for heating and cooking

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Kenyas Green Belt MovementIndividuals Matter

• Wangari Maathai founded the Green Belt Movement.
• The main goal is to organize poor women to plant
  (for fuelwood) and protect millions of trees.
• In 2004, awarded Nobel peace prize.

Figure 10-10A
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Boreal Forests

• Worlds largest biome
• Extensive clearcutting
• Primary source of worlds industrial wood and
  wood fiber

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Rangeland and Agricultural lands

• Rangeland
• Land that is not intensively managed and is used
  for grazing livestock

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Rangeland Degradation and Deforestation

• Overgrazing leaves ground barren
• Animals exceed their carrying capacity
• Land degradation
• Natural or human-induced process that decreases
  future ability of land to support crops or
  livestock
• Desertification
• Degradation of once fertile land into
  nonproductive desert

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Rangeland Trends in US

• Make up 30 of total US land area
• 2/3 privately owned
• Pressure from developers to subdivide
• Public rangeland managed by
• Taylor Grazing Act (1934)
• Federal Land Policy and Management Act (1976)
• Conditions of public rangeland are slowly
  improving
• Grazing fees is an issue

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Agricultural Land

• US has 300 million acres of prime farmland

• Much is being overtaken by suburban sprawl
• Parking lots
• Housing developments
• Shopping malls

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Wetlands

• Lands that are usually covered with water for at
  least part of the year
• Have characteristic soils and water-tolerant
  vegetation
• Benefits
• Habitat for migratory waterfowl and wildlife
• Recharge groundwater
• Reduce damage from flooding
• Improve water quality
• Produce many commercially important products

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Wetlands

• Human activity that threatens wetlands
• Drainage for agriculture or mosquito control
• Dredging for navigation
• Construction of dams, dykes or seawalls
• Filling in for solid waste disposal
• Road building
• Mining for gravel, fossil fuels, etc.
• Shrinking 58,500 acres per year

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Restoring Wetlands

• No Net Loss of Wetlands
• Development of wetlands is allowed if
  corresponding amount of previously converted
  wetland is restored
• Not all wetland restorations are successful

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Coastlines

• Coastal wetlands
• Provide food and habitat for many aquatic animals
• Historically regarded as wasteland

• US starting to see importance of protecting this
  environment
• Retaining seawalls (right)

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Coastal Demographics

• Many coastal areas overdeveloped
• 3.8 billion people live within 150km of coastline
• 6.4 billion people will likely live there by 2025

• United States
• 14 of 20 largest US cities along coast
• 19 of 20 most densely populated countries along
  coasts

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Conservation and Land Resources

• All types of ecosystems must be preserved
• Four criteria of importance
• Areas lost or degraded since European
  colonization
• Number of present examples of a particular
  ecosystem (or the total area)
• Estimate of the likelihood that a given ecosystem
  will lost a significant area or be degraded in
  next 10 years
• Number of threatened and endangered species
  living in the ecosystem

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Conservation and Land Resources
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SOURCE

• https//sites.google.com/a/siskorea.org/science-bi
  ts/ap-environmental-science/apes-assignments/ch-18
  -20-land-resources