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 most rapidly at an intermediate size –Population size is about half its carrying capacity –Managed populations are well below what they would naturally be Reducing populations so drastically affects other species and can change the entire ecosystem

Adaptive management evolves and improves Adaptive management = systematically testing different management approaches and aiming to improve methods –Time-consuming and complicated The 1994 Northwest Forest Plan resolved disputes between loggers and preservationists over the remaining old- growth temperate rainforests in the continental U.S. –Allowed limited logging –Protected species and ecosystems –Science-guided management in Oregon, Washington, and California

Ecological value of forests One of the richest ecosystems for biodiversity –Structural complexity houses great biodiversity A forest provides many ecosystem services –Stabilizes soil and prevents erosion –Slows runoff, lessens flooding, purifies water –Stores carbon, releases oxygen, moderates climate

Demand for wood leads to deforestation Deforestation = the clearing and loss of forests –Alters landscapes and ecosystems –Degrades soil –Causes species decline and extinction –Ruins civilizations –Adds carbon dioxide to the air Developing countries boost their economies and get land for their growing populations by logging forests

Deforestation in America and Canada Deforestation propelled the westward expansion and growth of America and Canada –Eastern deciduous forests were the first to be logged for farms and to build cities (i.e., Chicago) –Timber companies moved south to the Ozarks and west to the Rockies

Loggers moved westward, searching for large trees 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

Loggers lose their jobs with deforestation As each region is deforested, the timber industry declines and moves 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 The scarcity of remaining old-growth trees fuels scientific concerns and empassions environmentalists

Deforestation is proceeding rapidly worldwide Uncut tropical forests still remain in many developing countries –Technology allows for even faster exploitation –Deforestation is rapid in places such as Brazil and Indonesia Developing countries are so desperate for economic development, they have few logging restrictions – Short-term economic benefits go to foreign multinational corporations –Governments often help companies, at the expense of native people

Federal agencies own land in the U.S.

Most logging occurs on private land But, millions of cubic feet per year are still logged from national forests –Timber harvesting remains stable in developed countries –Timber companies manage forests according to the maximum sustained yield approach Management on public lands reflects economic forces, along with social and political ones

Plantation forestry The timber industry: timber plantations –Fast-growing species –Monocultures –Even-aged trees Trees are cut at the end of the rotation time and replanted –Plantations are crops, not functional forests Some harvesting methods maintain uneven-aged tree stands

Harvesting timber: clear-cutting –All trees in the area are cut –Most cost-efficient –Greatest impact on forest ecosystems –May mimic some natural forms of disturbance –Destroy entire communities –Soil erosion –Public is outraged over this type of harvesting

Harvesting:TABLE Seed-tree cutting = a small number of seed- producing trees are left standing to reseed the area Shelterwood cutting = a small number of trees are left to provide shelter for the seedlings 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 –Change forest structure and composition –Increase erosion, siltation, runoff, flooding, landslides –Selective is the BEST

Harvesting forests

Public forests can be managed for many things Increased public awareness caused people to urge changed forest management –For recreation, wildlife and ecosystem integrity, instead of logging –Critics protested federal subsidies of logging companies Multiple use policy = national forests were to be managed for recreation, habitat, minerals and other uses –In reality, timber production is the primary use The Forest Service loses $100 million/yr by selling timber below cost

The National Forest Management Act (1976) Mandated that plans for renewable resource management had to be drawn up for every national forest Guidelines included: –Consideration of both economic and environmental factors –Provision for species diversity –Ensuring research and monitoring –Permitting only sustainable harvests –Protection of soils and wetlands –Assessing all impacts before logging to protect resources

Fire policy also stirs controversy For over 100 years, the Forest Service suppressed all fires –But many ecosystems depend on fires –Fire suppression allows woody accumulation, which produces kindling for future fires Which are much worse Housing development near forests and climate change will increase fire risk

Prescribed fires are misunderstood Prescribed (controlled) burns = burning areas of forests under carefully controlled conditions –Effective –May get out of control –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

Salvage logging Removal of dead trees following a natural disturbance Seems logical, but is really destructive –Snags (standing dead trees) provide nesting cavities for countless animals –Removing timber from recently burned areas increases erosion and soil damage –Promotes future fires –Increases commercial logging in national forests –Decreases oversight and public participation

Sustainable forestry is gaining ground Sustainable forestry certification = only products produced sustainably can be certified –International Organization for Standardization (ISO), Forest Stewardship Council (FSC) have different standards –Consumers look for logos to buy sustainably produced timber –Companies such as Home Depot sell sustainable wood Encourages better logging practices

Agricultural land use Agriculture covers 38% of the Earths’ terrestrial surface –26% supports pasture, 12% supports crops –The most widespread type of land use –Causes tremendous environmental impacts Governments spend billions of dollars on subsidies –Proponents say farmers need this insurance against bad years –Critics say farmers should buy their own insurance

Wetlands have been drained for farming Many crop lands grow on former wetlands Governments have encouraged wetland draining –Promote settlement and farming –Transferred land to states –Stimulated draining Less than half the wetlands remain

Perspectives on wetlands are changing Many people have a new view of wetlands –Not worthless swamps, but valuable ecosystems –Demanded regulations to safeguard remaining wetlands –But, because of loopholes, wetlands are still being lost Conservation Reserve Program (1985) subsidized farmers to take highly erodable land out of production –Turn it into wildlife habitat

Livestock graze one-fourth of Earth’s land Grazing can be sustainable if done carefully and at low intensity Bureau of Land Management (BLM) = owns and manages most U.S. rangeland –Nation’s single largest landowner: 106 million ha (261 million acres) across 12 western states –Ranchers can graze cattle on BLM lands for low fees –Low fees encourage overgrazing Ranchers and environmentalists have joined to preserve ranchland against development and urban sprawl

Management of the American West Overexploitation of resources caused great damage to the American West –Poor farming practices, overgrazing, farming arid lands John Wesley Powell in the late 1800s called for agencies to base management on science –Farming Western lands had to account for arid conditions –His ideas were ignored, contributing to failures such as the Dust Bowl of the 1930s

Parks and reserves Reasons for establishing parks and reserves include: –Monumentalism = preserving areas with enormous, beautiful or unusual features, such as the Grand Canyon –Offer recreational value to tourists, hikers, fishers, hunters and others –Protect areas with utilitarian benefits, such as clean drinking water –Use sites that are otherwise economically not valuable and are therefore easy to protect –Preservation of biodiversity

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 of 1906 –The president can declare selected public lands as national monuments

The National Park Service (NPS) Created in 1916 to administer parks and monuments –388 sites totaling 32 million ha (72 million acres) –Includes national historic sites, national recreation areas, national wild and scenic rivers –273 million visitors in 2006

National Wildlife Refuges Begun in 1903 by President Theodore Roosevelt 37 million ha (91 million acres) in 541 sites U.S. Fish and Wildlife Service administers refuges –Management ranges from preservation to manipulation –Wildlife havens –Allows hunting, fishing, wildlife observation, photography, education

Wilderness areas Wilderness areas = area is off- limits to development of any kind –Open to the public for hiking, nature study, etc. –Must have minimal impact on the land –Necessary to ensure that humans don’t occupy and modify all natural areas Established within federal lands –Overseen by the agencies that administer those areas

Wilderness protection has been weakened President George W. Bush has weakened wilderness protection –Federal agencies have shifted policies and enforcement –Away from preservation and conservation –Toward recreation and resource extraction

Nonfederal entities also protect land Each U.S. state and Canadian province has agencies that manage resources –So do counties and municipalities Land trusts = local or regional organizations that purchase land to protect it –The Nature Conservancy is the world’s largest land trust –Trusts protect 4.1 million ha (10.2 million acres)

Biosphere reserves have several zones This can be a win-win situation for everyone

Habitat fragmentation threatens species Continguous habitat is chopped into small pieces –Species suffer

The SLOSS dilemma Which is better to protect species? –A Single Large Or Several Small reserves? –Depends on the species: tigers vs. insects Corridors = protected land that allows animals to travel between islands of protected habitat –Animals get more resources –Enables gene flow between populations