Transcript Chapter 10

Land Use: Landscapes, Forests,
Parks, and Reserves
Chapter 13 Botkin and Keller
Core Case Study:
Reintroducing Wolves to Yellowstone
 Endangered

1850-1900 two million
wolves were destroyed.
 Keystone



Species
Species
Keeps prey away from open
areas near stream banks.
Vegetation reestablishes.
Species diversity expands.
Figure 10-1
HUMAN IMPACTS ON TERRESTRIAL
BIODIVERSITY

We have depleted
and degraded
some of the
earth’s
biodiversity and
these threats are
expected to
increase.
Figure 10-2
Why Should We Care About
Biodiversity?
 Use
Value: For the
usefulness in terms
of economic and
ecological services.
 Nonuse Value:
existence, aesthetics,
bequest for future
generations.
Figure 10-3
Natural Capital
Forests
Ecological
Services
Support energy flow
and chemical cycling
Reduce soil erosion
Absorb and release
water
Economic
Services
Fuelwood
Lumber
Pulp to make paper
Mining
Purify water and air
Livestock grazing
Influence local and
regional climate
Recreation
Store atmospheric
carbon
Jobs
Provide numerous
wildlife habitats
Fig. 10-4, p. 193
Types of Forests
 Old-growth
forest: uncut
or regenerated forest that
has not been seriously
disturbed for several
hundred years.

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
22% of world’s forest.
Hosts many species with
specialized niches.
Mostly found in Russia,
Canada, Brazil, Indonesia,
Papua, New Guinea.
Figure 10-5
Types of Forests

Second-growth forest: a stand of trees resulting
from natural secondary succession.
 Tree plantation: planted stands of a particular tree
species; highly managed tree are uniform is size
Figure 10-6
Weak trees
removed
Clear cut
25
30
Seedlings
planted
15
Years of growth
10
5
Fig. 10-6, p. 195
Harmful Environmental Effects
Of Deforestation
• Decreased soil fertility from erosion
• Runoff of eroded soil into aquatic systems
• Premature extinction of species with
specialized niches
• Loss of habitat for native species and migratory
species such as birds and butterflies
• Regional climate change from extensive clearing
• Release of CO2 into atmosphere
• Acceleration of flooding
Fig. 10-7, p. 196
Deforestation and the Fuelwood
Crisis
 Almost
half the people in the developing
world face a shortage of fuelwood and
charcoal.

In Haiti, 98% of country is deforested.
Solutions to deforestation problem
1.
2.
3.
4.
Plant small tree plantations of fast growing
trees for fuel. Also tree nuts can be used as
protein source.
Provide cheap, efficient method for cooking
such as solar ovens or wind generated
electricity.
Burn dried roots of gourds.
MIT scientist has found a way to make
charcoal from spent sugarcane.
Harvesting Trees

Building roads into previously inaccessible forests
paves the way for fragmentation, destruction, and
degradation.
Figure 10-8
Harvesting Trees
 Trees
can be harvested
individually from diverse
forests (selective cutting),
an entire forest can be cut
down (clear cutting), or
portions of the forest is
harvested (e.g. strip
cutting).
Figure 10-9
(a) Selective cutting
1. Selective cutting: mark & cut individual trees;
usually smaller, poorly formed trees. Sometimes trees
of specific species are removed like mahogany.
2. Shelterwood cutting: cut dead & less desirable
trees; leave others to mature later.
3. Seed- tree cutting: removes all but a few seed trees
(mature trees w/ good genetics) to regenerate forest.
Fig. 10-9a, p. 198
Benefits of selective cutting
methods
1.
2.
3.
4.
5.
Reduces crowding
Removes diseased trees
Encourages growth of young trees
Maintains stand of trees of diff. species
Allows forest to be used in multiple ways
(b) Clear-cutting
Disadvantages of clear cutting
1. Changes chemical cycling like N2
2. Run off high
3. EROSION!!
4. Open to sunlight & rain ground temp. increases
5. Exposed soil decays rapidly
** Not always bad evaluate on case by case basis.
Fig. 10-9b, p. 198
(c) Strip cutting
Uncut
Cut 1
year ago
Dirt road
Cut 3–10
years ago
Uncut
Stream
Fig. 10-9c, p. 198
Strip Cutting advantages
1. Uncut strips protect trees from wind and
direct sunlight
2. Trees provide seeds
3. Minimizes negative aesthetic effects of
logging; leaves corridor for wildlife
4. More sustainable yield w/out widespread
destruction
Harvesting Trees
Effects of clear-cutting in the state of
Washington, U.S.
Figures 10-10 and 10-11
Trade-Offs
Clear-Cutting Forests
Advantages
Disadvantages
Higher timber yields
Reduces biodiversity
Maximum profits in
shortest time
Disrupts ecosystem
processes
Can reforest with fastgrowing trees
Destroys and
fragments wildlife
habitats
Short time to establish
new stand of trees
Leaves large openings
Needs less skill and
planning
Good for tree species
needing full or
moderate sunlight
Increases water
pollution, flooding, and
erosion on steep
slopes
Eliminates most
recreational value
Fig. 10-11, p. 198
Solutions
 We
can use forests
more sustainably by
emphasizing:

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
Economic value of
ecological services.
Harvesting trees no
faster than they are
replenished.
Protecting old-growth
and vulnerable areas.
Figure 10-12
Solutions
Sustainable Forestry
• Identify and protect forest areas high in biodiversity
• Grow more timber on long rotations
• Rely more on selective cutting and strip cutting
• Stop clear-cutting on steep slopes
• Cease logging of old-growth forests
• Prohibit fragmentation of remaining large blocks of
forest
• Sharply reduce road building into uncut forest areas
• Leave most standing dead trees and fallen timber for
wildlife habitat and nutrient recycling
• Certify timber grown by sustainable methods
• Include ecological services of forests in estimating
their economic value
• Plant tree plantations on deforested and degraded land
• Shift government subsidies from harvesting trees to
planting trees
Fig. 10-12, p. 199
FOREST RESOURCES AND
MANAGEMENT IN THE U.S.
 U.S.
forests cover more area than in 1920.
 Since the 1960’s, an increasing area of old
growth and diverse second-growth forests
have been clear-cut.
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Often replace with tree farms.
Decreases biodiversity.
Disrupts ecosystem processes.
Types and Effects of Forest Fires

Depending on their intensity, fires can benefit or harm
forests.
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Burn away flammable ground material; maintains habitat for small
mammals provides vegetation/sprouts after fire.
Release valuable mineral nutrients.
Certain plants (like chapparal plants) are regenerated by fire (seeds
only germinate after fire (giant sequoia, jack pine)
Figure 10-13
Solutions:
Controversy Over Fire Management

To reduce fire damage:
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
Set controlled surface
fires.
Allow fires to burn on
public lands if they don’t
threaten life and
property.
Clear small areas
around property subject
to fire.
3 types of fires
Surface fires
Crown fires
Ground fires
Burn away
surface litter
Most dangerous
extremely hot
Start as surface
go underground
Protect from
more destructive
fires later
releases,
nutrients, seeds,
controls insects
& pathogens
Leap from
Smolder for
ground to treetop days/weeks
Usually occur
Common in peat
where buildup of bogs
ground litter
Solutions:
Controversy Over Fire Management
 In
2003, U.S. Congress passed the Healthy
Forest Restoration Act:
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Allows timber companies to cut medium and
large trees in 71% of the national forests.
In return, must clear away smaller, more fireprone trees and underbrush.
Some forest scientists believe this could increase
severe fires by removing fire resistant trees and
leaving highly flammable slash.
Should Logging be allowed in U.S. National Forests?
Should U.S. national
forests be primarily
used for:
 Timber.
 Ecological services.
 Recreation.
 Mix of these uses.
Figure 10-14
Solutions:
Reducing Demand for Harvest Trees
 Tree
harvesting can
be reduced by
wasting less wood
and making paper
and charcoal fuel
from fibers that do
not come from trees.

Kenaf is a promising
plant for paper
production.
Figure 10-15
TROPICAL DEFORESTATION
 Large
areas of ecologically and
economically important tropical forests are
being cleared and degraded at a fast rate.
Figure 10-16
TROPICAL DEFORESTATION
 At
least half of the
world’s terrestrial plant
and animal species live
in tropical rain forests.
 Large areas of tropical
forest are burned to
make way for cattle
ranches and crops.
Figure 10-17
Why Should We Care about the Loss of
Tropical Forests?

About 2,100 of the 3,000 plants identified by the National
Cancer Institute as sources of cancer-fighting chemicals
come from tropical forests.
Figure 10-18
Causes of Tropical Deforestation and
Degradation

Tropical
deforestation
results from a
number of
interconnected
primary and
secondary
causes.
Figure 10-19
Solutions
Sustaining Tropical Forests
Prevention
Protect most diverse and endangered
areas
Restoration
Reforestation
Educate settlers about sustainable
agriculture and forestry
Phase out subsidies that encourage
unsustainable forest use
Add subsidies that encourage
sustainable forest use
Rehabilitation of degraded
areas
Protect forests with debt-for-nature
swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Concentrate farming and
ranching on already-cleared
areas
Fig. 10-20, p. 207
MANAGING AND SUSTAINING
GRASSLANDS
 Almost
half of the world’s livestock graze on
natural grasslands (rangelands) and
managed grasslands (pastures).
 We can sustain rangeland productivity by
controlling the number and distribution of
livestock and by restoring degraded
rangeland.
MANAGING AND SUSTAINING
GRASSLANDS
 Overgrazing
occurs when too
many animals
graze for too long
and exceed
carrying capacity
of a grassland
area.
Figure 10-21
MANAGING AND SUSTAINING
GRASSLANDS
 Example
of restored area along the San
Pedro River in Arizona after 10 years of
banning grazing and off-road vehicles.
Figure 10-22
NATIONAL PARKS
 Countries
have established more than 1,100
national parks, but most are threatened by
human activities.

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

Local people invade park for wood, cropland,
and other natural resources.
Loggers, miners, and wildlife poachers also
deplete natural resources.
Many are too small to sustain large-animal
species.
Many suffer from invasive species.
Stresses on U.S. National Parks
 Overused
due to
popularity.
 Inholdings (private
ownership) within
parks threaten
natural resources.
 Air pollution.
Figure 10-23
Suggestions for sustaining and
Expanding National Parks
• Integrate plans for managing parks and nearby
federal lands
• Add new parkland near threatened parks
• Buy private land inside parks
• Locate visitor parking outside parks and use
shuttle buses for entering and touring heavily
used parks
• Increase funds for park maintenance and repairs
• Survey wildlife in parks
• Raise entry fees for visitors and use funds for
park management and maintenance
• Limit the number of visitors to crowded park areas
• Increase the number and pay of park rangers
• Encourage volunteers to give visitor lectures and
tours
• Seek private donations for park maintenance and
repairs
Fig. 10-24, p. 211
NATURE RESERVES
 Ecologists
call for protecting more land to
help sustain biodiversity, but powerful
economic and political interests oppose doing
this.

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
Currently 12% of earth’s land area is protected.
Only 5% is strictly protected from harmful human
activities.
Conservation biologists call for full protection of
at least 20% of earth’s land area representing
multiple examples of all biomes.
NATURE RESERVES
A
model biosphere
reserve that
contains a protected
inner core
surrounded by two
buffer zones that
people can use for
multiple use.
Figure 10-25
NATURE RESERVES

Geographic Information System (GIS) mapping can be used
to understand and manage ecosystems.
 Identify areas to establish and connect nature reserves in
large ecoregions to prevent fragmentation.
 Developers can use GIS to design housing developments
with the least environmental impact.


We can prevent or slow down losses of biodiversity by
concentrating efforts on protecting global hot spots where
significant biodiversity is under immediate threat.
Conservation biologists are helping people in communities find ways to
sustain local biodiversity while providing local economic income.

34 hotspots identified by ecologists as important and
endangered centers of biodiversity.
Figure 10-26
NATURE RESERVES
 Wilderness
is land legally set aside in a
large enough area to prevent or minimize
harm from human activities.
 Only
a small percentage of the land area of
the United States has been protected as
wilderness.
ECOLOGICAL RESTORATION
 Restoration:
trying to return to a condition as
similar as possible to original state.
 Rehabilitation: attempting to turn a
degraded ecosystem back to being
functional.
 Replacement: replacing a degraded
ecosystem with another type of ecosystem.
 Re-creating artificial ecosystems: such as
artificial wetlands for flood reduction and
sewage treatment.
ECOLOGICAL RESTORATION
Five basic science-based principles for
ecological restoration:

1.
2.
3.
4.
5.
Identify cause.
Stop abuse by eliminating or sharply reducing
factors.
Reintroduce species if necessary.
Protect area form further degradation.
Use adaptive management to monitor efforts,
assess successes, and modify strategies.
What Can You Do?
Sustaining Terrestrial Biodiversity
• Adopt a forest.
• Plant trees and take care of them.
• Recycle paper and buy recycled paper products.
• Buy sustainable wood and wood products.
• Choose wood substitutes such as bamboo furniture
and recycled plastic outdoor furniture, decking, and
fencing.
• Restore a nearby degraded forest or grassland.
• Landscape your yard with a diversity of plants
natural to the area.
• Live in town because suburban sprawl reduces
biodiversity.
Fig. 10-27, p. 219