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Published byShane Pinks Modified over 9 years ago
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Land
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Land Use in the World
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US Public Lands
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Types of Forests 1) Old-growth (primary) forests – uncut or regenerated forest not hugely impacted by humans or natural disaster for 200 years or more
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Types of Forests 2) Second-growth forests – a forest resulting from secondary ecological succession
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Types of Forests 3) Tree farms/plantation (Commercial forest) – A managed forest containing only one or two types of trees that are all the same age.
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Ecological Importance of Forests Food webs and energy flow Water regulation Influence local-regional climate Numerous habitats and niches Air purification Carbon sequestration
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Economic Importance of Forests $ Fuel wood (50% of global forest use) $ Industrial timber and lumber $ Pulp and paper $ Medicines $ Mineral extraction $ Recreation
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Forest Structure Floor Understory Canopy Emergent
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Forest Structure
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Forest Management Even-aged management Industrial forestry
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Foresting Cutting and Regrowth
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Uneven-aged management Improved diversity Sustainable production Selective cutting Multiple-use
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Logging Roads result in increased erosion and runoff habitat fragmentation pathways for exotic species accessibility to humans
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Harvesting Trees selective cutting- Trees can be harvested individually from diverse forests clear cutting- an entire forest can be cut down, or portions of the forest is harvested (e.g. strip cutting).
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Forests are renewable resources as long as the rate of cutting and degradation does not exceed the rate of re-growth.
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Depending on their intensity, fires can benefit or harm forests.
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1) Surface/Ground Fire Burn away flammable ground material Release mineral nutrients Increase activity of nitrogen-fixing bacteria Stimulate germination of some seeds Help control pathogens and insects
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Crown Fire Destroys most vegetation Kills wildlife Increases soil erosion
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Forest Resources Sustained yield potentially renewable resources should not be harvested or used faster than they can be reproduced Only 3% of timber harvest comes from national forests Substitutes for tree products Tree-free fibers
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Substitutes for tree products Tree-free fibers agricultural residues (i.e. sugarcane bagasse, husks and straw) fiber crops and wild plants, such as bamboo, kenaf, hemp, jute, and flax textiles wastes
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Reducing Demand Tree harvesting can be reduced by wasting less wood and making paper and charcoal fuel from fibers that do not come from trees. Kenaf is a promising plant for paper production.
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TROPICAL DEFORESTATION Large areas of ecologically and economically important tropical forests are being cleared and degraded at a fast rate
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TROPICAL DEFORESTATION At least half of the world’s terrestrial plant and animal species live in tropical rain forests. Large areas of tropical forest are burned to make way for cattle ranches and crops.
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Tropical Deforestation: Consequences Rapid and increasing Loss of biodiversity Loss of resources (e.g., medicines) Contributes to global warming
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Baiji dolphin Spix's macaw
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Types of Forests 1)Old-growth (primary) forests – uncut or regenerated forest not hugely impacted by humans or natural disaster for 200 years or more 2)Second-growth forests – a forest resulting from secondary ecological succession 3)Tree farms/plantation (Commercial forest) – A managed forest containing only one or two types of trees that are all the same age.
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Harvesting Trees selective cutting- Trees can be harvested individually from diverse forests clear cutting- an entire forest can be cut down, or portions of the forest is harvested (e.g. strip cutting).
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Tropical Deforestation: Consequences Rapid and increasing Loss of biodiversity Loss of resources (e.g., medicines) Contributes to global warming
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BLM lands (Bureau of Land Management)- grazing, mining, timber harvesting and recreation USFS lands (US Forest Service)- timber harvesting, grazing and recreation NPS lands (National Park Service)- recreation and conservation FWS lands (Fish and Wildlife Service)- wildlife conservation, hunting, and recreation
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National Parks- established to preserve scenic views and unusual landforms. National wildlife refuges- managed for the purpose of protecting wildlife National wilderness areas- set aside to preserve large tracts of intact ecosystems or landscapes.
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National Environmental Policy Act (NEPA)- mandates an environmental assessment of all projects involving federal money or permits. Environmental impact statement (EIS)- outlines the scope and purpose of the project. Environmental mitigation plan- outlines how the developer will address concerns raised by the projects impact on the environment.
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