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1 Land Use: Forests World Land Uses World Forests Tropical Forests Temperate Forests What is a forest?
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2 CS Fig 12.3 2 Includes all wooded land, whether in Old-growth, secondary growth, or plantation
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3 CS Fig 12.3 3
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4 World Resources Institute: Frontier forest 8,000 years ago http://www.igc.org/wri/forests/index.html Frontier forests = undisturbed by humans
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5 World Resources Institute: Frontier forest today Frontier forests = undisturbed by humans
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7 Fig 12.3
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8 Forest Distribution Almost one half of original forests and woodlands have been converted to other uses. –Currently, forests and woodlands cover 32% of earth’s land surface. (4.2 billion ha) –Greatest concern is over protection of Old-Growth Forests. Only 22% of forests still retain old-growth characteristics.
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9 Reasons Forests are Important to Nature Help regulate climate (O 2 /CO 2 ) Minimize surface water runoff Provide wildlife habitat Purify water and air Scenic, cultural, and historical value (why it’s good to leave forests intact)
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10 Mudslides after Hurricane Mitch
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11 Forest Products Wood plays a part in more activities of the modern economy than any other commodity. –Industrial Timber and unprocessed logs account for about half of worldwide wood consumption. Timber Paper Fuel (raw wood and charcoal) Developed countries produce less than half of all industrial wood, but account for about 80% of consumption. (why people want to cut forests down)
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12 CS Fig 12.7 Which kind of forest is being lost more than any other right now?
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13 Satellites make it possible to document deforestation accurately (and to the minute)
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15 Fig. 14.12 Cattle grazing in Costa Rica Settlers encroach when roads are built
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16 Reason for Tropical Forest Losses Governments Building Paved Roads –Make it possible to access forest products for logging more economically Demographic Transition –Many people in developing countries practice subsistence farming –As population grows, area cut for farms grows
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17 Effect of paving roads in Brazilian rainforest CS Fig 12.8
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19 Forests cut for farming as population in US grew Some forests re-grow after demographic transition
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20 The choices of a Costa Rican land owner “Mine” forest – one infusion of cash –Then: Plantations – wait for trees to grow in Cattle ranch – severe erosion created Sustainable forestry –What is incentive to practice sustainable forestry? –Who benefits? Land owner or society? Incentive for forest- friendly policy making
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21 Regions in North America where Primary Forest Threatened Source: WRI
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22 Ancient Forests of the Pacific Northwest Redwoods can reach 3-4 m in diameter, 90 m in height and 1,000 years in age. –Temperate rainforests are second only to tropical rainforests in terrestrial biodiversity. Accumulate more biomass in standing vegetation per unit area than any other ecosystem on earth. Less than 10% of virgin temperate rainforest remain (80% scheduled to be cut in the near future).
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23 Clear cuts in Washington State’s Gifford Pinchot Nat. Forest, Fig. 12.12
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25 What is threatening species? Fragmentation of forests Lack of age structure Lack of diversity Atmospheric pollution Can have quantity, but without quality it’s not the same
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26 Northern Spotted Owl CS Fig 12.16
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27 The last logger?
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28 How do we manage a forest sustainably? Clear cutting? Not on a large scale Alternatives: Selective cutting Strip cutting Clear cut with small and large reserve areas Fire?
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29 Selective Cutting Small percentage of trees removed over 10-20 year rotation Thin so that improves growth of remaining trees Maintains some of age structure of old-growth forest Logs taken out carefully Reduces erosion and run-off Case study: Menominee Nation (p. 244)
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30 Strip Cutting Harvest all trees in narrow strip No burning or crops Strip quickly regenerates (seeds nearby) Use both large and small trees in tropical forest, better than selective cutting
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34 Williams 1989
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38 Below-Cost Salvage Sales USFS has historically regarded its primary job as providing a steady supply of cheap logs to the nation’s timber industry. –Often, timber prices have not been enough to repay management costs. Hidden subsidy to timber industry. –USFS builds roads in order for timber companies to extract trees.
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39 What can YOU do? Reuse and recycle paper! Market is booming right now! Use e-mail/conserve paper Buy sustainably harvested wood Don’t eat at fast-food restaurants that purchase beef from cattle grazing on deforested rainforest land (rainforestweb.org)rainforestweb.org Buy sustainably harvested goods from forests (see the Forest Stewardship Council at www.fscus.org)www.fscus.org
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40 The End. Back to Syllabus
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