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lect04-13-10 - Readings(April 13 April 15 Miller and...

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Unformatted text preview: Readings (April 13 April 15) Miller and Spoolman, Chapters 9, 10 and 24 (pp. 640- 642) "The Future of Forests: Tree-Lover, Spare the Woodman" The Economist, June 22, 1991 Ferraro, P. and R. D. Simpson "Cost-Effective Conservation; A Review of What Works to Preserve Biodiversity" Resources, Spring 2001, pp.17-20 - http://www.rff.org/rff/documents/rff-resources-143.pdf Types of Forests about 30% of earth's land surface is forested climatic conditions (e.g., temperature & precipitation) influence forest characteristics examples of forest types - tropical, temperate, boreal roughly half of world's forests are in tropics age of forest is important - old-growth vs. secondgrowth forests tropical & old-growth forests are disappearing rapidly Worldwide Distribution of Forests Worldwide Distribution of Forests Problem of Deforestation about 8% tropical forests are lost over a ten year period two-thirds of European & most of U.S. oldgrowth forests are already gone Management of Private Forests about 25% of world's forests are managed to produce wood rotations are cycles of growth & harvest rotation length is selected to maximize profits Management of Private Forests systems of forest management even-aged - production of same species, age, size (mono-culture tree farms) uneven-aged - simultaneous production of diverse types & ages harvesting practices selective-cutting vs. clear-cutting Management of Private Forests selective cutting involves removing only some trees this allows natural regeneration from surrounding trees Management of Private Forests clearcutting involves removing all trees site is generally planted with seedlings, leading to evenage stands soil erosion can be severe after clear-cutting National Forests & Other Public Lands governments often own a significant share of land in forests & other wildlife habitat in U.S., such public lands fall into three categories: 1) multiple-use lands, which include National Forests (National Forest Service) & National Resource Lands (Bureau of Land Management) 2) moderately-restricted use lands, which include National Wildlife Refuges (U.S. Fish & Wildlife) 3) restricted-use lands, which include National Parks (National Park Service), & the National Wilderness Preservation System National Forests & Other Public Lands in U.S. 35% of U.S. land is public 73% of this land is in Alaska, while 22% is in western U.S. (60% of land in western U.S. is public) Multiple-Use Lands in U.S. management of multiple-use public lands in the U.S. is supposed to follow two guiding principles principle of sustainable yield - potentially renewable resources (such as trees) should not be harvested or used faster than they are replenished principle of multiple use - the same land should be managed simultaneously for a variety of uses (e.g., timber harvest, grazing, recreation, & wildlife conservation) Multiple-Use Lands in U.S. National Forest System - 155 forests & 22 grasslands nation-wide, managed by the U.S. Forest Service (USFS) dominant use of National Forests has been logging USFS is the largest road builder, building roads to subsidize logging operations National Resource Lands - mostly in western states & Alaska, managed by the Bureau of Land Management (BLM) dominant use of national resource lands is grazing & supply of mineral & energy resources - grazing permits are generally sold at a price far below prices in private lands Old-Growth Forests old-growth forests are uncut & regenerated forests that have not been seriously disturbed for several hundred or thousands of years temperate examples include forests of Douglas fir, western hemlock, giant sequoia, & coastal redwoods in the western U.S., and boreal forests in Russia, western Canada, & Alaska old growth forests have a diversity of tree ages, dead trees (snags), & fallen logs such forests provide niches for multitude of species Old-Growth Forests in U.S. since 1600 most of the old-growth forests in the lower 48 states have been cleared ...
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