chapter 10

• ecological and economic services of forests:

  oxygen

  lumber

  medicine

  raw materials

  food

  hydrologic and carbon cycles
• Why haven't we included the loss of Earth's ecological services that are lost each year into our accounting system?

  Lack of full cost pricing
• 3 types of forests:

  Primary forests

  Second growth

  Tree plantation
• Primary forests: forests uncut/undisturbed for 200 or more years
• Second growth: trees that come from secondary succession
• Tree plantation: Same age trees clear cut and replanted to supply industrial wood
• Monoculture: one plant grown throughout an entire given area of land
• Polyculture: Several plants grown throughout a given area of land through alternating rows or crop cycling
• What percentage of the world’s forests have been cut down?

  50%
• Problems associated with deforestation:

  removes habitats

  increases CO2 in atmosphere

  removes resources

  increases soil erosion

  increases flooding
• Selective cutting:

  when trees that are matured are cut, while the trees that are still maturing are not cut
• Clear-cutting forestS:

  fast and efficient

  unsustainable and will lead to the tragedy of the commons
• sustainablestrip-cutting:

  Rather than cutting the entire area , the area is cut into strips. More sustainable
• 6 ways to manage our forests sustainable:

  • Emphasize the value of their ecosystem services 
  • Halt government subsidies that hasten their destruction
  • Protect old growth forests
  • Harvest trees no faster than they replenish
  • Plant trees to establish forests
  • Removing certain trees which would otherwise hurt the environment
• 2 types of forest fires:

  1. surface fires
  2. crown fires
• 3 reasons why we should care about our rainforests:

  1. Rich with resources and recreational opportunities
  2. multiple chemical cycles
  3. acts as a habitat for 50% of all terrestrial species
• Causes of rainforest deforestation and degradation

  • poverty
  • population growth
  • ranching
  • lumber
  • plantation farms
• What methods can be used to sustain forests?

  • Emphasize the value of their ecosystem services
  • Halt government subsidies that hasten their destruction
  • Protect old growth forests
• ways to restore degraded forests:

  • Replant trees
  • Convert farmland to forest
  • Government pays landowners to restore forests
• Overgrazing: Reduces grass coverage and compacts the soil, reducing its ability to hold water
• Undergrazing: Cattle helps destroy dead grass and speeds decomposition, so undergrazing actually makes the growth slower
• Effects of overgrazing: Reduces grass coverage and compacts the soil, reducing its ability to hold water
• Threats to national parks in developing country:

  • illegal poaching
  • mining
  • logging
• Ecological hotspots - areas that are rich in biodiversity but are highly threatened
• 1964 Wilderness Act: U.S. government prohibits commerical activity in public lands
• Habitat corridor - bridges or other connections that allow migration of species between areas or reserves
• Buffer zone concept - a barrier between urban areas and core reserve areas
• Ecoregion - areas where ecosystems are very similar