Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition

Lecture Outlines Chapter 12 Environment:The Science behind the Stories 4th Edition Withgott/Brennan

Notes HW • Write each slide title on the left side of the paper • Summarize provided information on the right side of the paper • If there are slides with Objectives or “this lecture will help you understand” you do NOT need to write these. • Define any words or answer any questions or fill in the blanks when something appears in red. • Sometimes it is a question linked to a website you should view • Sometime there are comments written in purple. You do not need to write these. They are just my personal commentary  • Be prepared to answer questions at the end.

This lecture will help you understand: • Ecological and economic contributions of forests • History and scale of deforestation • Forest management and harvest methods • Major federal land management agencies • Types and design of protected areas

Central Case: Certified sustainable paper • The paper in your book is made from trees sustainably grown, managed, harvested, and processed • This does not deplete mature trees or degrade ecological functions • The mill recycles chemicals and paper and burns discarded lignin to help provide power Forest Stewardship Council (FSC)-certified from sources that use sustainable practices

Forests cover 31% of Earth’s surfaceForest ? Rainbow Eucalyptus or Rainbow Gum

A cross-section of a mature forest • Canopy ? • Understory ? • Snag ? • Ground cover ?

Forests provide ecosystem services Forests provide cultural, aesthetic, health, and recreation values: i.e. Benefits: medicines, food, fuel, shelter, ships, paper Forests provide vital ecosystem services Stabilize soil and prevent erosion Slow runoff, prevent flooding, purify water Store carbon, release oxygen, influence weather patterns, and moderate climate Roots draw minerals to surface soil layers Plants return organic material to the topsoil as litter

Carbon storage helps limit climate change • Trees absorb carbon dioxide and store carbon • Preserving forests keeps carbon out of the atmosphere/ Cutting intensifies climate change • Dead plants decompose and release carbon dioxide • Fewer trees soak up less carbon dioxide

Demand for wood leads to deforestation Deforestation = the clearing and loss of forests Changes landscapes and ecosystems Reduces biodiversity Worsens climate change Disrupts ecosystem services Ruins civilizations (Easter Island)

Deforestation propelled the expansion and growth of the U.S. and Canada Primary/ Old-growth forest ? Little remained by the 20th century Secondary forest ? Smaller trees, very different species and structure

Rapid deforestation in developing nations • Uncut tropical forests still remain in many developing countries (Brazil, Indonesia, and West Africa) • Developing countries are so desperate for economic development, they have few logging restrictions • Concession ? • Temporary jobs are soon lost, along with the resources • Wood is exported to North America and Europe

REDD = Reducing Emissions from Deforestation and Forest DegradationFrom the 2009 Copenhagen climate conferenceWealthy nations would pay poor nations to conserve forests • The Copenhagen conference ended without a binding agreement

Forest management Forestry (silviculture) = forest management Sustainable forest management is spreading Resource management =strategies to manage and regulate potentially renewable resources Maximum sustainable yield ?

Fear of a “timber famine” spurred forest protection • Depletion of eastern U.S. forests caused alarm • National forest system = public lands set aside to grow trees, produce timber, protect watersheds, and ensure future timber supplies • 77 million ha (191 million acres)—8% of U.S. land area • The U.S. Forest Service was established in 1905 • Manages forests for the greatest good of the greatest number in the long run • Management includes logging and replanting trees

Timber is extracted from public and private land • Private companies extract timber from public land • The Forest Service plans and manages timber salesand builds roads • Companies log and sell the timber for profit Taxpayers subsidize private timber harvesting on public land

Logging on private vs. public land • Most U.S. logging occurs on private land owned by timber companies or small landowners • Companies use the maximum sustained yield approach • Management on public lands reflects social and political factors that change over time • But the secondary forests that replace primary forests are less ecologically valuable

Plantation forestry • The timber industry focuses on timber plantations • Fast-growing, single-species monocultures • Even-aged stands ? • Rotation time = trees are cut after a certain time • The land is replanted • Uneven-aged stands ? Tree plantations are crops, not ecologically functional forests

Harvesting timber: clear-cutting • All trees in the area are cut • Most cost-efficient • Greatest ecological impact • May mimic some natural disturbance (e.g., storms) • Leads to soil erosion Clear-cutting destroys entire communities

Harvesting: other methods • Seed-treeapproach ? • Shelterwoodapproach ? • Selective cutting ? • Single tree selection = widely spaced trees are cut • Group tree selection = small patches of trees are cut • However, All methods disturb habitat and affect species • Change forest structure and composition • Increased runoff, flooding, erosion, siltation, landslides

Harvesting forests B A C Which type of logging is shown in each picture?

The National Forest Management Act (1976) • Every national forest must formulate plans for renewable resource management that: • Consider both economic and environmental factors • Provide for and protect regional diversity • Ensure research and monitoring of management • Permit only sustainable harvest levels • Ensure that profit alone does not guide harvest method • Protect soils and wetlands • Assess 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 • Excess vegetation produces kindling for future fires

Three types of fires affect forest ecosystems • Surface fires- burn underbrush, burn leaf litter, and most seedlings, but most wildlife survive • Crown fires- extremely hot and leap from treetop to treetop • Ground fires- most common in northern peat bogs where they go underground and burn decaying matter

Prescribed (controlled) burns = burning areas of forests under carefully controlled conditions • Clear away fuel loads, nourish soil, encourage growth of new vegetation • Are time-intensive • Are impeded by public misunderstanding and political interference • Some trees (Jack Pine) need fire to release seeds

Solutions: Controversy Over Fire Management • In 2003, U.S. Congress passed the Healthy Forest Restoration Act: • Allows timber companies to cut medium and large trees in 71% of the national forests. • In return, must clear away smaller, more fire-prone trees and underbrush. • Some forest scientists believe this could increase severe fires by removing fire resistant trees and leaving highly flammable slash.

Salvage logging • Removal of dead trees following a natural disturbance • It seems logical, but is really destructive • Snags (standing dead trees) provide nesting and roosting cavities for countless animals • Removing timber from recently burned areas increases erosion and soil damage • Impedes forest regeneration and promotes future fires

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 (1906) lets the president declare public lands as national monuments • Which may later become national parks

The National Park Service (NPS) • Created in 1916 to administer parks and monuments • 392 sites totaling 34 million ha (84 million acres) • Includes national historic sites, national recreation areas, national wild and scenic rivers • 285 million visitors in 2009 • These parks are “the best idea we ever had” • There are also 3,700 state parks across the U.S.

National Wildlife Refuges • Begun in 1903 by President Theodore Roosevelt • U.S. Fish and Wildlife Service (USFWS) • Administers wildlife refuges, serving as havens • But allows hunting, fishing, wildlife observation, photography, education • Managed for waterfowl and non-game species • Restores marshes and grasslands

Wilderness areas are on federal lands Wilderness areas = are off-limits to development • For hiking, nature study, etc. • Must have minimal impact • Grazing and mining were allowed as political compromise • Established in federal lands • Overseen by the agencies that administer those areas

Not everyone supports land set-asides • The wise-use movement ? • To protect private property, oppose government regulation • Federal lands transferred to state or private hands • Motorized recreation on public lands • Farmers, ranchers, loggers, mineral, and fossil fuel industries

Protected areas • Biosphere reserves = land with exceptional biodiversity • Couple preservation with sustainable development • Benefit local people

World heritage sites • Another type of international protected area • Transboundary parks/ Peace parks = protected land overlapping national borders • Peace Park- Costa Rica and Panama • Land trusts = local or regional organizations that purchase land to protect it • The Nature Conservancy is the world’s largest land trust

Effects of habitat fragmentation • Logging, agriculture, and residential development fragment habitat • Edge effects ? • Area effect = large islands have more species than small • They have more habitats, environments, and variety

Island biogeography theory = explains how species come to be distributed among islands(can be aquatic or terrestrial) • Distance effect: the farther an island is from the continent, the fewer species find and colonize it • Larger islands have higher immigration rates – they are fatter targets • Larger islands have lower extinction rates – more space allows for larger populations

The species-area curve • Species-area curves ? • Protected parks are small “islands” surrounded by development (farms, roads, cities) • Many parks are missing species and are too isolated to berecolonized

Reserve design has consequences • The SLOSS dilemma = which is better to protect species: a single large or several small reserves? • Depends on the species: tigers vs. insects • Corridors ? • Animals get more habitat • Enables gene flow between populations

CH 12-A • Why do natural primary forests contain more biodiversity than secondary forests and single-species forestry plantations? • Name 3 ecosystems services provided by forests. How does deforestation contribute to climate change? • Name several major causes of deforestation. How does changing a forested area into an impervious surface affect the water cycle? Where is deforestation most severe today? • Give one advantage and one disadvantage of each of the following types of silviculture: clear cutting, seed tree/ shelterwood cutting, & selective cutting.

CH 12-B • What are the three main types of forest fires? Are forest fires a bad thing? Explain. • What is island biogeography theory and how is it being used today? • Describe the role of each of the following: Healthy Forest Restoration Act, National Forrest Management Act, Antiquities Act, U.S. Forest Service, National Parks Service, U.S. Fish and Wildlife Service

QUESTION: Review Which of the following is NOT part of the ecological value of forests? a) Erosion prevention b) Decreased flooding c) Carbon storage d) All of the above are values of forests.

QUESTION: Review Which of the following statements regarding forest management is false? a) Deforestation in the U.S. has occurred for centuries. b) Timber companies move on after an area is deforested. c) Tropical countries have lost the majority of forests so timber companies won’t be going there. d) Governments in developing countries help logging companies at the expense of native people.

QUESTION: Review If an area is managed for Maximum Sustainable Yield, and the area can support 100 organisms, how many organisms will be allowed to remain in the area? a) 100 b) 75 c) 50 d) 25

QUESTION: Review Which agency manages national forests? a) U.S. Fish and Wildlife Service b) U.S. Forest Service c) Bureau of Land Management d) National Park Service

QUESTION: Review Tree harvesting by clear-cutting: a) Cuts all trees in an area, leaving only stumps b) Cuts most trees, but leaves some to produce seeds c) Cuts most trees, but leaves some to shelter seedlings d) Produces uneven-aged tree stands

QUESTION: Review The National Forest Management Act of 1976 guidelines included all of the following, EXCEPT: a) Consideration of economic factors b) Soil protection c) Increased harvesting under times of economic stress even if not sustainable d) Provisions for species diversity

Lecture Outlines Chapter 12 Environment: The Science behind the Stories 4th Edition