Chapter 13 Environmental Geography: Land Resources

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Chapter 13 Environmental Geography Land
Resources
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Selected Federal Lands
Federal govt owns 35 U.S. land --Resource
use, --Cultural significance, --Habitat --Where
is this land?
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U.S. Land Use

• Provide ecosystem services
• Help determine human impact on ecosystems
• Recreational value
• Spiritual value

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Forests

• Less than 1/3 Earths area
• What do we use forests for?
• Ecosystem services
• Help regulate biogeochemical cycles
• Carbon sinks
• Release O2
• Protect watersheds
  how?
• Provide habitat

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Harvesting Trees

• 2004 3.4 million cubic feet of wood harvested
• Some burned directly
• Charcoal production
• Paper and wood products
• Some wood
  ecologically
  certified FSC (Forest Stewardship Council

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Forest Management

• Sustainable forestry
• Practices vary
• Environmentally balanced
• Maintain mix of trees
• Long-term conservation
• Wildlife corridors
• Connects areas
• Help some populations

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Selective cutting vs. Clear cutting

• Mature trees cut individually
• Forest remains essentially intact
• Suitable for regenerating shade-tolerant species
• Spreads impact over larger area

• All trees in an area are cut
• Area re-seeds naturally or planted
• Suitable for regenerating pioneer tree species
• Common and controversial
• Heavy impact over smaller area

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Selective cutting
Clear cutting

• To get the same amount of trees from selective
  cutting as from clear cutting,
• you need a lot more roads
• More forest is disturbed by logging equipment

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Deforestation

• Clearing large expanses of forests
• Most serious problem facing forests today
• Why is this occurring?
• Most in Africa and
  South America

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Results of Deforestation

• Decreased soil fertility
• Increased soil erosion
• Desertification
• Increased extinction
• Climate changes how?

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Deforestation Boreal Forests

• Alaska, Canada, Scandinavia, Russia
• Extensive by late 1980s
• Used for wood, wood fiber
• Annual loss area twice as large as Brazils
  rain forests

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Tropical Rain Forests

• Central South America, Africa, SE Asia

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Deforestation Tropical Rain Forests

• Subsistence agriculture
• Farmers follow roads
• Slash-and-burn
• Later used for ranching
• Commercial logging
• Cattle ranching
• Dam building
• Mining

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U.S. National Forests

• 155 national forests
• 191 million acres
• Where are these forests?
• What are they used for?
• Multiple-use lands
• Road building

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Allegheny National Forest
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Rangelands

• Grasslands not intensively managed
• Livestock grazing
• Grasses, forbs, shrubs

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Rangeland Degradation

• Grazing
• Can be beneficial
• Carefully manage
• Can increase plant diversity
• Dont exceed carrying capacity
• Result of overgrazing and drought ?
  desertification

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U.S. National Park System

• Created in 1916
• 388 sites (58 parks)
• 84.3 million acres
• Purpose
• Protect natural wonders
• Education
• Recreation

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Threats to U.S. Parks

• Too many visitors
• Crime, vandalism, litter
• Some access now limited

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Threats to U.S. Parks

• Wildlife imbalances
• Not enough predators
• Yellowstone
• Too many elk
• Wolf reintroduction has
  helped
• Surrounded by development

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How Should Federal Lands Be Managed?

• Wise-use movement
• Lands are for resource use
• National forests should be logged
• Mining development
• Unrestricted wetland development
• ESA needs changes
• Sell some lands

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How Should Federal Lands Be Managed?

• Environmental movement
• Lands for protecting biodiversity
• No subsidies for resource use
• Hold those who damage land accountable

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Homework

• Read Ellison et al. (2005) Loss of foundation
  species consequences for the structure and
  dynamics of forested ecosystems
• Choose one of the three species discussed
  (hemlock, whitebark pine, or chestnut)
• Draw a model showing how removal of the
  foundation species affects ecosystem function
• Include information on historical vs.
  present-day
• Ecological processes
• Biotic factors
• Abiotic factors