Transcript Forest - Cabarrus County Schools

Chapter 12 Topics:
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Ecological and economic contributions of forests
History and scale of deforestation
Forest management
and harvest methods
U.S. forest policy,
origin and challenges
Types and design
of protected areas
Many kinds of forests exist
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Forest = any ecosystem with a high density of trees
Plant communities differ due to soil and climate
Forest types are defined by predominant tree species
Boreal forest = in Canada, Scandinavia, and Russia
 Tropical rainforest = South and Central America, Africa,
Indonesia, and southeast Asia
 Temperate deciduous forests, temperate rainforests, and
tropical dry forests also exist
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Woodlands = ecosystems with lower density of trees
Distribution of forests
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Forests cover 31% of Earth’s surface
Forests in the U.S.
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The Eastern U.S. has 10 forest types
 Spruce-fir,
 Oak-hickory
 Longleaf-slash
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pine
The Western U.S. holds 13 forest types
 Douglas
fir
 Ponderosa pine
 Pinyon-juniper
woodlands
Forests are ecologically complex
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Forests can have very rich biodiversity
Structurally complex, with many niches; provide food
and shelter for multitudes of species
Plant diversity leads to greater overall diversity
Succession changes species composition
Old-growth forest
diversity exceeds
that of young
forests due to
higher structural
diversity, habitats,
and resources
Forests provide ecosystem services
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Forests provide cultural, aesthetic, health, and
recreation values
Forests also 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
 Cycle nutrients via root uptake and leaf litter decay
Carbon storage limits climate change
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Carbon storage by forests is of great international
interest as nations debate climate change
 Trees
absorb carbon dioxide and store carbon
 The world’s forests store 280 billion metric tons of C
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Cutting forests worsens climate change
 Dead
plants decompose and release carbon dioxide
 Fewer trees soak up less carbon dioxide
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Preserving forests keeps carbon out of the
atmosphere
Forests provide valuable resources
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Primary resource is timber (lumber, fuel, paper)
 Boreal
forests: Canada, Russia
 Rainforests: Brazil, Indonesia
 Conifer forests/
plantations: U.S.
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Other benefits:
medicines, food
Worldwide, forests
are designated for
many uses
Demand leads to deforestation
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Deforestation = the clearing and loss of forests
 Changes
landscapes and ecosystems
 Reduces biodiversity and disrupts ecosystem service
 Worsens climate change
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Deforestation rate
is slowing
Still lose 12.8 million
acres/year
Deforestation fed U.S. growth
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Eastern deciduous forests harvested first, then south
to the Ozarks, then west to the Rockies
Primary forest = natural forest uncut by people
Secondary forest = contains second-growth trees
(smaller trees, different species and forest structure)
Deforestation – current trends
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Uncut tropical forests remain in many developing
countries (Brazil, Indonesia, and West Africa)
Technology allows for even faster exploitation
Developing countries are desperate for economic
development and have few logging restrictions
Concession = corporations pay the government
for the right to extract resources
 Wood
is exported to North America and Europe
 Temporary jobs are soon lost, along with the resources
Palm oil plantations
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Palm oil is used in snack
foods, soaps, cosmetics,
biofuel
Pesticides and fertilizers
from palm oil agriculture
disrupt ecosystems
Clearing encourages
further development and
illegal logging
Borneo has lost most of its
forest cover
Reducing deforestation
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Conservation concessions = organizations team up to
reduce deforestation and illegal logging
Carbon offsets = curb deforestation & climate change
(forest loss = 12–25% greenhouse gas emissions)
Reducing Emissions from Deforestation and Forest
Degradation (REDD)
REDD emerged from 2009 Copenhagen climate conference
 Wealthy nations would pay poor nations to conserve forests
 Guyana could earn $580 million/year by cutting forests
 Norway will pay $270 million by 2015 for conservation
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Forest management
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Forestry (silviculture) = forest management
Foresters = professional managers who balance
demand for forest products (short-term benefits) vs.
the importance of forests as ecosystems (long term)
Resource management = strategies to manage
and regulate potentially renewable resources
 Sustainable
management does not deplete resources
 Managers are influenced by social, political, and
economic factors
Maximum sustainable yield
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Maximum sustainable yield = aims to achieve the
maximum amount of resource extraction without
depleting the resource from one harvest to the next
Populations grow fastest when the population size is
at half its carrying capacity
Harvesting to keep the population at this size results
in maximum harvest while sustaining the population
Problems with this approach
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Managed populations are smaller than natural ones
Reducing populations affects other species,
changing the entire ecosystem
Trees are cut before
they grow to maximum
size, changing forest
ecology, eliminating
habitats
Ecosystem-based management
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Ecosystem-based management = managing resource
harvesting to minimize impacts on ecosystems and
ecological processes
Sustainably certified forestry plans protect areas
Restore ecologically important habitats
 Consider patterns at the landscape level
 Preserve the forest’s functional integrity
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It is challenging to implement this type of management
Ecosystems are complex
 Our understanding of how they operate is limited
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Adaptive management
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Adaptive management = testing different approaches
and aiming to improve methods through time
Monitoring results and adjusting methods as needed
 Time-consuming and complicated, but effective
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The 1994 Northwest Forest Plan resolved disputes
between loggers and preservationists over the last
U.S. old-growth temperate rainforests
The plan let science guide management
 Allowed limited logging but protected species & ecosystems
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The origin of U.S. forest policy
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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 (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
Current trends – private land
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Most U.S. logging occurs on private land owned by
timber companies using maximum sustained yield
The timber industry focuses on timber plantations (fastgrowing, single-species monocultures)
Even-aged stands= all
trees the same age, cut
at same time, replanted
Uneven-aged stands
mixed ages/species
Tree plantations are
crops, not ecologically
functioning forests
Current trends – public land
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Logging also occurs on public land (subsidized)
 The
Forest Service plans/manages sales, builds roads
 Private companies log and sell the timber for profit
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Management on public lands reflects social and
political factors that change over time
 Public
concern, changing management philosophies, and
economics have caused harvests to decrease
 But the secondary forests that replace primary forests
are less ecologically valuable
Harvesting methods – clear-cutting
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Clear-cutting = all trees in the area are cut
 Greatest ecological impact
 Most cost-efficient
 May mimic some
natural disturbance
(e.g., storms)
 Leads to soil erosion
Public outrage caused
companies to use other
harvesting methods
Harvesting methods - alternative
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Seed-tree approach = a few seed-producing trees
are left standing to reseed the logged area
Shelterwood approach = some trees are left to
provide shelter for the seedlings as they grow
Selection systems = only select trees are cut
 Single
tree selection = widely spaced trees are cut
 Group tree selection = small patches of trees are cut
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All methods disturb habitat and affect species
 Change
forest structure and composition
 Increased runoff, flooding, erosion, siltation, landslides
Managing public forests
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Increased public awareness caused people to urge
that forests be managed for recreation, wildlife,
and ecosystem integrity, instead of only for logging
Multiple use policy =
national forests are
supposed to be
managed for recreation,
habitat, minerals, and
other uses, but timber
production is still the
primary use
National Forest Management Act
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In 1976, new law required every national forest
formulate plans for 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
Implementing the NFMA
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U.S. Forest Service developed new programs:
 Ecosystem-based
management of wildlife, non-game
animals, endangered species
 Ecological restoration projects
 Timber cuts that mimic natural events
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Politics influence forestry management
 Bush
administration loosened environmental protections
and restricted public oversight
 The roadless rule, which protected 31% of national
forests from logging, repealed in 2004
 Court rulings reinstated the roadless rule in 2009
Fire policy
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Since 1095, Forest Service has suppressed all fires
Growing recognition that this may need to change
 Many
ecosystems depend on fires
 Excess vegetation produces kindling for future fires
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The wildland-urban interface,
housing developments near
forests, are vulnerable
Catastrophic fires have
become more numerous
Fire as a management tool
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Prescribed (controlled) burns = burning areas of
forests under carefully controlled conditions
 Clear
away fuel loads, nourish soil, encourage growth
 Time-intensive; impeded by public misunderstanding
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Healthy Forests Restoration Act (2003) = promotes
removal of small trees, underbrush, and dead trees
Salvage logging
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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
Climate change is altering forests
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The U.S. is getting warmer and drier
Large fires are linked to weather conditions
Pest outbreaks are linked to weather conditions
Woodlands, shrub lands, or grasslands may replace
forests
Sustainable forestry initiatives
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Sustainable forest certification = sustainably
produced products certified by organizations
 Forest
Stewardship Council (FSC) has strictest standards
 Companies such as Home
Depot sell sustainable
wood, encouraging
better logging practices
 Consumers look for logos
to buy sustainably
produced timber
Protected lands
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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
The National Park Service (NPS)
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Created in 1916, administers 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
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These parks are “the best idea we ever had”
There are also 3,700 state parks across the U.S.
National Wildlife Refuges
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Begun in 1903 by President Theodore Roosevelt
 39
million ha (96 million acres) in 550 sites
 The Pacific Remote Islands Marine National Monument
added 22 million ha (55 million acres)
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U.S. Fish and Wildlife Service (USFWS)
 Administers
wildlife refuges
 Allows for hunting, fishing, wildlife observation,
photography, education
 Managed for waterfowl and non-game species
 Restores marshes and grasslands
Wilderness areas
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Wilderness areas = are off-limits to development
Established within federal lands and overseen by
the agencies that administer those lands
756 areas, 44 million ha
(109 million acres)
For minimal impact activities
(hiking, nature study)
Grazing/mining were
allowed as political compromise
Opposition to protected land
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Opposition to restricted use of public lands is more
common in the western U.S. where much of the land
is owned by the Federal government
“The wise-use movement” = individuals and industries
opposed to environmental protection want Federal
lands transferred to state or private hands
During Bush Administration, Federal agencies shifted
policies away from preservation and conservation
toward recreation and resource extraction
Other land protection
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Each U.S. state has agencies that manage resources
on public lands as do many counties and
municipalities
Land trusts = local or regional organizations that
purchase land to protect it
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Nature Conservancy is the world’s largest land trust
 Trusts own 690,000 ha (1.7 million acres) and protect
an additional 4.1 million ha (10.2 million acres)
 Jackson Hole, Wyoming is protected by a land trust
International trends
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Many nations have established national parks
Protect areas cover 12% of the world’s land area
Parks do not always receive necessary funding
Biosphere reserves = land with exceptional
biodiversity
Couple preservation with sustainable development
World Heritage sites = 890 sites in 148 countries listed
for their natural or cultural value
Designing protected lands
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Studying the effects of habitat fragmentation
informs the design of protected lands
Logging, agriculture, and
residential development
fragment habitat
Fragmentation is the main
reason populations of
North American songbirds
are declining
Effects of habitat fragmentation
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Edge effects = conditions along edges are
different than conditions in the interior
 Interior
bird species can’t reproduce when forced
near an edge
 Nest are vulnerable to parasites and predators from
the other habitat
Fragments are like islands
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Island biogeography theory = explains how
species come to be distributed among islands
The number of island species results from a balance
between species added versus species lost
Predicted by the island’s distance
from the mainland and its size
Distance effect: the farther an
island is from the continent, the
fewer species find and colonize it
Island biogeography
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Area effect = large
islands have more species
 They
have more habitats,
environments, and variety
 They have higher
immigration rates – they
are fatter targets
 They have lower extinction
rates – more space allows
for larger populations
Parks as islands
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The size and placement of
protected areas are key
to protecting biodiversity
Protected parks are small
“islands” surrounded by
development (farms,
roads, cities)
The SLOSS dilemma =
which is better to protect
species: a single large or
several small reserves?
Protected areas & climate change
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Global climate change threatens to undo our efforts
to design, establish, and guard protected areas
Species try to shift northward with warmer
temperatures but species can’t move in a
fragmented habitat
High-elevation species are most at risk because
there is no place for them to go
Corridors to allow movement become important
Take-aways
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We are losing ecologically and environmentally
valuable forests
Resource management policies first emphasized
extraction; then shifted to sustained yield and
multiple use
Sustainable forest certification provides economic
incentives for responsible conservation of forests
Public support for land preservation resulted in
parks and protected areas in the U.S. and abroad