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CHAPTER 23

CHAPTER 23 . Sustaining Terrestrial Biodiversity: The Ecosystem Approach . Key Concepts. Human land use. Types and uses of US public lands. Forests and forest management. Implications of deforestation. Management of parks. Establishment and management of nature preserves.

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CHAPTER 23

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  1. CHAPTER 23 Sustaining Terrestrial Biodiversity: The Ecosystem Approach

  2. Key Concepts • Human land use • Types and uses of US public lands • Forests and forest management • Implications of deforestation • Management of parks • Establishment and management of nature preserves • Importance of ecological restoration

  3. Who’s Afraid of the Big Bad Wolf? http://www.youtube.com/watch?v=dMGJ9oThHbc

  4. Land Use in the World Fig. 23-2 p. 595

  5. I. Land Use In The United States • A. PUBLIC LANDS(42%) - 35% of land in the United States is designated as public and is managedby the Federal Government. - Classified as… 1. Multiple-Use Lands ** ”National Forests” 2. Moderately Restricted-use ** “National Wildlife Refuges”Lands (hunting, fishing, oil and gas development, mining, logging, farming, military, etc…) 3. Restricted-use Lands (only camping, hiking, fishing, boating) ** “National Parks”

  6. State and local 7% Federal 35% Native American 3% Private 55% U.S. Land Ownership

  7. National wildlife refuges National parks and preserves National forests

  8. 1. Multiple-Use Lands Include… - 155 Forests and 20 Grasslands of the NATIONAL FOREST SYSTEM • Managed by the U.S. FOREST SERVICE and - NATIONAL RESOURCE LANDS- Managed by the Bureau of Land Management

  9. 2. Moderately Restricted-Use Lands Include… - 522 NATIONAL WILDLIFE REFUGES - Managed by the U.S. Fish and Wildlife Service

  10. 3. Restricted-Use Lands Includes…the NATIONAL PARK SYSTEM - 379 units of which include 55 major parks and 324 national recreation areas. - Managed by the National Park Service and - 630 roadless areas of the NATIONAL WILDERNESS PRESERVATION SYSTEM Majority in Alaska

  11. National parks and preserves National forests National wildlife refuges

  12. How should the lands be managed? Federal public lands contain valuable resources: • 20% of oil reserves • 30 % of natural gas • 40 % forest • large amounts of minerals

  13. 2 opposing viewpoints Developers point of view: • Sell public lands or their resources • Unregulate public lands • Replace old growth forests with tree plantations • Drill, mine, and commercially develop national parks Conservation biologists point of view: • Protect biodiversity: habitats should be primary goal • No subsidies or tax breaks for using resources • Compensation for use of property • Take responsibility for any environmental damage

  14. 23-2 Managing and Sustaining Forests(32% of earth land surface) Economic Services -Fuelwood, 50% -Timber and Roundwood -Pulp -Medicines Ecological Services -Support food webs -Act as sponge to absorb pollution -Influence local climate -Habitat

  15. A. MAJOR TYPES OF FORESTS TROPICAL(47%) , subtropical(9%) temperate(11%) , BOREAL/POLAR(33%) • B. CATEGORIES OF FORESTS… 1. OLD-GROWTH FOREST 2. SECOND-GROWTH FOREST 3. TREE PLANTATION

  16. 1. OLD-GROWTH FOREST -FRONTIER FOREST -Undisturbed by humans and/or natural disasters for hundreds of years -Very BIODIVERSE due to increased recycling of nutrients and good habitat

  17. Layers of biodiversity Emergent/Dominant Canopy/Codominant Understory/Intermediate Floor/Suppressed Subsoil

  18. SECOND GROWTH FORESTS Result fromSECONDARY SUCCESSION as a result of human activities or natural disaster(s)

  19. 3. TREEPLANTATION or TREE FARMS *An attempt to produce products more efficiently by setting back secondary succession. *Often referred to as MONOCULTURE *GROWS ONLY ONE SPECIES *Harvested as soon as they become VALUABLE and then replanted.

  20. Long rotations Old-growth harvest (such as hardwoods for furniture) • C. TYPES OF FOREST MANAGEMENT - The total volume of wood produced by a strand of forest VARIES as it goes through different STAGES of growth and succession B C Wood volume or wood biomass A Short rotation(pulp) Time

  21. Weak trees removed Seedlings planted Clear cut 25 15 10 30 5 Years of growth

  22. - Two basic forest management techniques… • Even-Aged Management: -Also called INDUSTRIAL FORESTRY - Trees are kept as same size and age Ex: TREE FARM OR PLANTATION *Extensive research has shown that soil become depleted

  23. 2. UnEven-Aged Management: • Trees are kept at a variety of ages and sizes. • -Goals are; biological diversity, long-term sustainable production of timber, moderate economical return, and multiple use of forests. *The rate of economic return plays a major role in the technique used.

  24. D. HARVESTING TECHNIQUES 1. Selective Cutting: - Intermediate-aged or mature trees in an uneven-aged forest are cut singly or in small groups -reduces crowding -encourages growth -protects against soil erosion -maintains uneven growth

  25. Selective Cutting

  26. Selective Cutting: (continued) -a special type of selective cut is used called… high grading -High Grading is when only the largest and best species are used.

  27. 2. Shelterwood Cutting: -Removes all mature trees in two/three cuttings over a period of 10 years. -allows natural regeneration -reduces soil erosion -provides good habitat for wildlife

  28. Cut 2 Cut 1 Shelterwood Cutting

  29. 3. Seedtree Cutting: -Harvests nearly all a stand’s trees in onecutting, leaving a few seed-producing trees behind to regenerate the area. -Leads to genetic improvement in new stands

  30. Seed-Tree Cutting

  31. 4. Clear Cutting: -Removal of alltrees from an area in a single cutting; either the whole stand, a strip, or a series of patches.

  32. Clear-Cutting

  33. CONS - LEAVES LARGE OPENINGS IN FOREST - REDUCES BIO- DIVERSITY - INCREASES SOIL EROSION - DECREASES RECREATION PROS - INCREASE YIELD - IMPROVES STOCK - LESS SKILL NEEDED - INCREASED $ - BEST WAY TO HARVEST TREE FARMS

  34. 5. Strip Cutting: -Type of clear-cut that removes a strip of trees along the contour of the land, narrow enough to allow for natural regeneration -Strips are harvested every 30-40 years

  35. Uncut Cut Cut Cut Uncut 1 year ago 3–5 years ago 6–10 years ago Strip Cutting

  36. F. FOREST SUSTAINABILITY HOW?? -Longer rotation of timber growth -Emphasize selective cuttingand strip -Minimize fragmentation -Leave snags and down timber -Use proper anti-erosion techniques

  37. F. FOREST PESTS/DISEASE 1.Parasitic Fungi: accidental chestnut blight (China) dutch elm (Asia) white pine blister (Europe)

  38. Bark beetle 2. Parasitic Insects: Gypsy moth Hemlock woolly adelgid

  39. G. FOREST AND FOREST FIRES - important part of ecological cycle of some forests and grasslands Types of Forest Fires: 1. Surface Fires- burn leaf litter and ground clutter

  40. Surface fire Fig. 23.12a, p. 599

  41. 2. Crown fire-Burn in the treetops -most dangerous of all fires

  42. Crown fire

  43. 3. Ground Fires-Underground and burn partially decayedor peat -Common in pet bogs

  44. H. Forest Fire Prevention: -Fire prevention Techniques are a controversial subject -Since 1972, the policy on forest fires has been to let them burn themselves outas long as not a danger to humans. -After fires of 1994 and 2000, many calls for change.

  45. Techniques Used- *prevention *prescribed burning *pre-suppression *supression

  46. 23-3 ForestResources/Management in the US • Today’s Status: • Forest covers about 1/3 of the lower 48 United States. • Forest are generally bigger and healthier than in 1920. • Among most diverse in the world

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