CHAPTER 10

• Old-growth or primary forest

  Uncut or undisturbed for 200 years or more, reservoirs of biodiversity
• Second-growth forest


  Trees from secondary ecological succession
• Tree plantation (tree farm, commercial forest)

  Same-age trees clear-cut and replanted to supply industrial wood
• Forests remove CO2 from the atmosphere and help stabilize atmospheric temperatures
• Forests store water and release it slowly
• Forests provide habitats for two-thirds of world's terrestrial species
• Forests provide biofuel, industrial wood, and traditional medicines
• Ecosystem services provided by forests

  • Removing CO2 from atmosphere
  • Stabilizing atmospheric temperatures
  • Storing and releasing water slowly
  • Providing habitats for terrestrial species
  • Providing biofuel, industrial wood, and traditional medicines
• Ecological economists estimate value of earth's ecosystem services at around $125 trillion per year
• Examples of ecosystem services valued at trillions per year

  • Waste treatment ($22.5 trillion)
  • Recreation ($20.6 trillion)
  • Erosion control ($16.2 trillion)
  • Food production ($14.8 trillion)
  • Nutrient cycling ($11.1 trillion)
• Forests account for at least $15.6 trillion per year in ecosystem services
• Since 1997 world has been losing ecosystem services valued at $20.2 trillion per year
• Full-cost pricing


  Including the value of ecosystem services in prices of forest goods and services
• Harvesting trees


  1. Building logging roads

  2. Selective cutting

  3. Clear-cutting

  4. Strip cutting
• Surface fires


  • Usually burn leaf litter and undergrowth, provide several ecological benefits
• Crown fires


  • Extremely hot, burn whole trees, kill wildlife, increase topsoil erosion
• Climate change is lengthening fire seasons
• Occasional fires


  • Burn away dry brush, free nutrients, release seeds, stimulate germination, control insects and diseases
• Pine bark beetles have devastated large areas of conifer forests due to warmer climate
• Deforestation


  Temporary or permanent removal of large expanses of forest for agriculture, settlements, or other uses
• Tropical forests have experienced especially high rates of deforestation, especially in Latin America, Indonesia, and Africa</b>
• Boreal forests have experienced especially high rates of deforestation, especially in Alaska, Canada, Scandinavia, and Russia
• Some countries like Costa Rica and the United States have increased forest cover, often through tree plantations

  
• China pays individuals to stop logging forests and reforest logged lands, cutting deforestation rate in half and sharply reducing flooding
• Negative impacts of deforestation

  • Water pollution
  • Soil degradation from erosion
  • Acceleration of flooding
  • Local extinction of specialist species
  • Habitat loss for native and migrating species
  • Release of CO2 and loss of CO2 absorption
• Forests of the eastern United States were decimated between 1620 and 1920 but have grown back naturally through secondary ecological succession
• Large areas of old-growth and second-growth forests in the US have been cleared and replaced with biologically simplified tree plantations, a growing threat is hardwood forests being cleared to produce wood pellets for export
• Majority of tropical deforestation has occurred since 1950, mostly in Africa, Southeast Asia, and South America, accelerating climate change
• Causes of tropical deforestation

  • Population growth
  • Poverty of subsistence farmers
  • Ranching
  • Lumber
  • Plantation farms—palm oil
  • Global trade
• May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
• Case Study


  Many Cleared Forests in the United States Have Grown Back
• Majority of tropical forest loss since 1950
• Mostly in Africa, Southeast Asia, South America
• Clearing trees accelerates climate change
• Indonesia leads world in tropical deforestation
• Destroying rain forest to produce palm oil
• Causes of tropical deforestation

  • Population growth
  • Poverty of subsistence farmers
  • Ranching
  • Lumber
  • Plantation farms—palm oil
  • Global trade
• As of the end of August 2019, the Amazon rainforest in Brazil had more than 80,000 reported fires. This was a 77% increase from the previous year's dry season.
• Scientists believe a combination of slash-and-burn agriculture, above average temperatures, and an unusually long dry season have contributed.
• Methods to sustain forests

  • Emphasize the value of their ecosystem services
  • Halt government subsidies that hasten their destruction
  • Protect old-growth forests
  • Harvest trees no faster than they are replenished
  • Plant trees to reestablish forests