Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition Withgott/Brennan - PowerPoint PPT Presentation

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Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition Withgott/Brennan

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Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition Withgott/Brennan
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Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition Withgott/Brennan

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  1. Lecture Outlines Chapter 12 Environment:The Science behind the Stories 4th Edition Withgott/Brennan

  2. This lecture will help you understand: • Ecological and economic contributions of forests • History and scale of deforestation • Forest management and harvest methods • Major federal land management agencies • Types and design of protected areas

  3. Central Case: Certified sustainable paper • The paper in this book is made from trees sustainably grown, managed, harvested, and processed • This does not deplete mature trees or degrade ecological functions • The mill recycles chemicals and paper and burns discarded lignin to help provide power This paper is Forest Stewardship Council (FSC)-certified from sources that use sustainable practices

  4. Many kinds of forests exist • Forest = any ecosystem with a high density of trees • Boreal forest = in Canada, Scandinavia, and Russia • Tropical rainforest = South and Central America, Africa, Indonesia, and southeast Asia • Temperate deciduous forests, temperate rainforests, and tropical dry forests also exist • Woodlands = ecosystems with lower density of trees • Plant communities differ due to soil and climate • Forest types = are defined by predominant tree species

  5. Forests cover 31% of Earth’s surface

  6. Forest types • The Eastern U.S. has 10 forest types • Spruce-fir, oak-hickory, longleaf-slash pine • The Western U.S. holds 13 forest types • Douglas fir, ponderosa pine, pinyon-juniper woodlands

  7. Forests are ecologically complex • Forests are some of the richest ecosystems for biodiversity • They are structurally complex, with many niches • They provide food and shelter for multitudes of species • Fungi and microbes have parasitic and mutualistic relationships with plants • Plant diversity leads to greater overall organism diversity • Succession changes species composition • Old-growth forest diversity exceeds that of young forests • They have higher structural diversity, habitats, and resources

  8. A cross-section of a mature forest The scarlet tanager lives in the eastern U.S. temperate deciduous forest

  9. Forests provide ecosystem services Forests provide cultural, aesthetic, health, and recreation values Forests also provide vital ecosystem services Stabilize soil and prevent erosion Slow runoff, prevent flooding, purify water Store carbon, release oxygen, influence weather patterns, and moderate climate Roots draw minerals to surface soil layers Plants return organic material to the topsoil as litter

  10. Carbon storage helps limit climate change • Carbon storage by forests is of great international interest • Nations debate how to control climate change • Trees absorb carbon dioxide and store carbon • The world’s forests store 280 billion metric tons of C • Cutting forests worsens climate change • Dead plants decompose and release carbon dioxide • Fewer trees soak up less carbon dioxide • Preserving forests keeps carbon out of the atmosphere

  11. Forests provide us valuable resources Benefits: medicines, food, fuel, shelter, ships, paper Help us achieve a high standard of living Logging locations: Boreal forests: Canada, Russia Rainforests: Brazil, Indonesia Conifer forests/pine plantations: U.S. In 2010, 30% of all forests were designated for timber production

  12. Demand for wood leads to deforestation Deforestation = the clearing and loss of forests Changes landscapes and ecosystems Reduces biodiversity Worsens climate change Disrupts ecosystem services Ruins civilizations Although the rate of deforestation is slowing, we still lose 12.8 million acres/year

  13. Deforestation fed the growth of the U.S. Deforestation propelled the expansion and growth of the U.S. and Canada Eastern deciduous forests were the first to be logged Timber companies moved south to the Ozarks, west to the Rockies Primary forest = natural forest uncut by people Little remained by the 20th century Second-growth trees = grown to partial maturity after old-growth timber has been cut Secondary forest = contains second-growth trees Smaller trees, very different species and structure

  14. Most primary forest is gone The entire eastern half of the continent used to be covered in primary forest Most primary forest was cut for agriculture and timber

  15. Loggers lose their jobs with deforestation • As each region is deforested, the timber industry declines and timber companies move on • Local loggers lose their jobs • Once the remaining ancient trees of North America are gone, loggers will once again lose jobs • Companies will simply move to another area • Most move to developing countries

  16. Rapid deforestation in developing nations • Uncut tropical forests still remain in many developing countries (Brazil, Indonesia, and West Africa) • Technology allows for even faster exploitation • Developing countries are so desperate for economic development, they have few logging restrictions • Concession = corporations pay the government for the right to extract resources • Temporary jobs are soon lost, along with the resources • Wood is exported to North America and Europe

  17. Deforestation affects people • In Malaysia, foreign corporations have deforested millions of acres of tropical rainforest • Affecting 22 tribes of hunter-gatherers • The government did not consult the tribes • Deforestation decreased game • Oil palm agriculture’s pesticides and fertilizers killed fish • The people peacefully protested • The government wants to convert tribes to farmers

  18. Palm oil plantations • Palm oil is used in snack foods, soaps, cosmetics, biofuel • Borneo has lost most of its forest cover • Clearing encourages further development and illegal logging

  19. Solutions to deforestation are emerging • Conservation concessions = organizations team up to reduce deforestation and illegal logging • Carbon offsets = curb deforestation and climate change • Forest loss causes 12–25% greenhouse gas emissions • The Kyoto Protocol does not address this • REDD = Reducing Emissions from Deforestation and Forest Degradation • From the 2009 Copenhagen climate conference • Wealthy nations would pay poor nations to conserve forests

  20. REDD • The Copenhagen conference ended without a binding agreement • The REDD plan fell through • But some of the $100 billion/year going to poor nations may go to REDD • Guyana is taking a leading role in REDD • It is poor financially but rich in forests • Cutting forests would provide $580 million/year • Norway will pay $20 million in 2010 for conservation and up to $250 million in 2015

  21. Forest management Forestry (silviculture) = forest management Sustainable forest management is spreading Foresters = professional managers who must balance demand for forest products (short-term benefits) vs. the importance of forests as ecosystems (long term) Resource management =strategies to manage and regulate potentially renewable resources Sustainable management does not deplete resources Managers are influenced by social, political, and economic factors

  22. Maximum sustainable yield Maximum sustainable yield =aims to achieve the maximum amount of resource extraction without depleting the resource from one harvest to the next Populations grow fastest at an intermediate size Population size is at half its carrying capacity Harvesting to keep the population at this size results in maximum harvest While sustaining the population

  23. Maximum sustainable yield has problems • Managed populations are much smaller than they would naturally be • Reducing populations so drastically affects other species • Changing the entire ecosystem • Trees are cut long before they grow to maximum size • Changing forest ecology • Eliminating habitats

  24. Ecosystem-based management Ecosystem-based management = managing resource harvesting to minimize impacts on ecosystems and ecological processes Sustainably certified forestry plans protect areas Restore ecologically important habitats Consider patterns at the landscape level Preserve the forest’s functional integrity It is challenging to implement this type of management Ecosystems are complex Our understanding of how they operate is limited

  25. Adaptive management Adaptive management = testing different approaches and aiming to improve methods through time Monitoring results and adjusting methods as needed Time-consuming and complicated, but effective The 1994 Northwest Forest Plan resolved disputes between loggers and preservationists over the last U.S. old-growth temperate rainforests The plan let science guide management It allowed limited logging while protecting species and ecosystems

  26. Fear of a “timber famine” spurred forest protection • Depletion of eastern U.S. forests caused alarm • National forest system = public lands set aside to grow trees, produce timber, protect watersheds, and ensure future timber supplies • 77 million ha (191 million acres)—8% of U.S. land area • The U.S. Forest Service was established in 1905 • Manages forests for the greatest good of the greatest number in the long run • Management includes logging and replanting trees

  27. Federal agencies own land in the U.S.

  28. Timber is extracted from public and private land • Private companies extract timber from public land • The Forest Service plans and manages timber salesand builds roads • Companies log and sell the timber for profit Taxpayers subsidize private timber harvesting on public land

  29. Logging on private vs. public land • Most U.S. logging occurs on private land owned by timber companies or small landowners • Companies use the maximum sustained yield approach • Management on public lands reflects social and political factors that change over time • Public concern, changing management philosophies, and economics have caused harvests to decrease • But the secondary forests that replace primary forests are less ecologically valuable

  30. Plantation forestry • The timber industry focuses on timber plantations • Fast-growing, single-species monocultures • Even-aged stands= all trees are the same age • Rotation time = trees are cut after a certain time • The land is replanted • Uneven-aged stands = mixed ages of trees and species Tree plantations are crops, not ecologically functional forests

  31. Harvesting timber: clear-cutting • All trees in the area are cut • Most cost-efficient • Greatest ecological impact • May mimic some natural disturbance (e.g., storms) • Leads to soil erosion • Public outrage caused companies to use other harvesting methods • Clear-cutting destroys entire communities

  32. Harvesting: other methods • Seed-tree approach = a few seed-producing trees are left standing to reseed the logged area • Shelterwood approach = some trees are left to provide shelter for the seedlings as they grow • Selection systems = only select trees are cut • Single tree selection = widely spaced trees are cut • Group tree selection = small patches of trees are cut • All methods disturb habitat and affect species • Change forest structure and composition • Increased runoff, flooding, erosion, siltation, landslides

  33. Harvesting forests Clear-cut logging Selection logging Seed-tree and shelterwood logging

  34. Managing public forests • Increased public awareness caused people to urge that forests be managed for recreation, wildlife, and ecosystem integrity, instead of only for logging • Critics protest federal subsidies of logging companies • Multiple use policy = national forests are to be managed for recreation, habitat, minerals, and other uses • In reality, timber production is the primary use The Forest Service loses $100 million/year of taxpayer money and increased harvest by selling timber below cost

  35. The National Forest Management Act (1976) • Every national forest must formulate plans for renewable resource management that: • Consider both economic and environmental factors • Provide for and protect regional diversity • Ensure research and monitoring of management • Permit only sustainable harvest levels • Ensure that profit alone does not guide harvest method • Protect soils and wetlands • Assess all impacts before logging to protect resources

  36. New forestry • U.S. Forest Service programs: • Manage wildlife, non-game animals, endangered species • Push for ecosystem-based management • Run programs for ecological restoration • New forestry = timber cuts that mimic natural events • Sloppy clear-cuts mimic windstorms

  37. Politics influences forestry management • The Bush administration rolled back regulations in 2004 • Freed managers from requirements of the National Forest Management Act • Loosened environmental protections • Restricted public oversight • Repealed President Clinton’s roadless rule, which protected 31% of national forests from logging • State governors had to petition the federal government to protect areas • Court rulings reinstated the roadless rule in 2009

  38. Fire policy also stirs controversy • For over 100 years, the Forest Service suppressed all fires • But many ecosystems depend on fires • Excess vegetation produces kindling for future fires • In the wildland-urban interface, housing developments that are near forests are vulnerable to forest fires Catastrophic fires have become more numerous recently

  39. Prescribed fires are misunderstood • Prescribed (controlled) burns = burning areas of forests under carefully controlled conditions • Clear away fuel loads, nourish soil, encourage growth of new vegetation • Are time-intensive • Are impeded by public misunderstanding and political interference • Healthy Forests Restoration Act (2003)= promotes removal of small trees, underbrush, and dead trees • Passed in response to forest fires

  40. Salvage logging • Removal of dead trees following a natural disturbance • It seems logical, but is really destructive • Snags (standing dead trees) provide nesting and roosting cavities for countless animals • Removing timber from recently burned areas increases erosion and soil damage • Impedes forest regeneration and promotes future fires

  41. Climate change is altering forests • The U.S. is warming and getting drier and will get worse • Pests kill huge areas of trees, particularly plantations • Dead trees do not remove carbon dioxide • Intensifying climate change • Woodlands, shrublands. or grasslands may replace forests Increased fires and pests destroy large areas of the U.S.

  42. Progress toward sustainable forestry is mixed • The world is still losing forested land • But advances are being made toward sustainable forestry

  43. Sustainable forestry is gaining ground • Sustainable forest certification = products produced sustainably can be certified by organizations • The Forest Stewardship Council (FSC) has the strictest standards • Companies such as Home Depot sell sustainable wood, encouraging better logging practices • Consumers look for logos to buy sustainably produced timber Strong certification standards drive sustainability

  44. Why create parks and reserves? • People establish parks and reserves to: • Preserve areas with enormous or unusual scenic features, such as the Grand Canyon • Offer recreational value: hiking, fishing, hunting, etc. • Generate revenue from ecotourism • Offer peace of mind, health, exploration, wonder, etc. • Protect areas that provide ecosystem services • Use sites that are otherwise economically not valuable and are therefore easy to protect • Preserve biodiversity

  45. Federal parks and reserves began in the U.S. • National parks = public lands protected from resource extraction and development • Open to nature appreciation and recreation • Yellowstone National Park was established in 1872 • The Antiquities Act (1906) lets the president declare public lands as national monuments • Which may later become national parks

  46. The National Park Service (NPS) • Created in 1916 to administer parks and monuments • 392 sites totaling 34 million ha (84 million acres) • Includes national historic sites, national recreation areas, national wild and scenic rivers • 285 million visitors in 2009 • These parks are “the best idea we ever had” • There are also 3,700 state parks across the U.S.

  47. National Wildlife Refuges • Begun in 1903 by President Theodore Roosevelt • 39 million ha (96 million acres) in 550 sites • The Pacific Remote Islands Marine National Monument added 22 million ha (55 million acres) • U.S. Fish and Wildlife Service (USFWS) • Administers wildlife refuges, serving as havens • But allows hunting, fishing, wildlife observation, photography, education • Managed for waterfowl and non-game species • Restores marshes and grasslands

  48. Wilderness areas are on federal lands Wilderness areas = are off-limits to development • For hiking, nature study, etc. • Must have minimal impact • Grazing and mining were allowed as political compromise • Established in federal lands • Overseen by the agencies that administer those areas • 756 areas, 44 million ha (109 million acres) • Wilderness is necessary to ensure that humans don’t occupy and modify all natural areas

  49. Not everyone supports land set-asides • Some western states want resource extraction and development • The wise-use movement = individuals and industries opposed to environmental protection want: • To protect private property, oppose government regulation • Federal lands transferred to state or private hands • Motorized recreation on public lands • Farmers, ranchers, loggers, mineral, and fossil fuel industries

  50. Opposition to wilderness protection • President George W. Bush weakened wilderness protection • Federal agencies shifted policies and enforcement away from preservation and conservation toward recreation and resource extraction • Indigenous people often oppose land protection • Recreational areas are often sacred to Native cultures • But protected areas can help indigenous people • In Brazil and other Latin American nations, these areas protect tribes from miners, farmers, and settlers