CHAPTER 23

Sustaining Terrestrial

Biodiversity: The Ecosystem Approach

Key Concepts

Human land use Human land use

Types and uses of US public lands Types and uses of US public lands

Forests and forest management Forests and forest management

Implications of deforestation Implications of deforestation

Management of parks Management of parks

Establishment and management of nature

preserves

Establishment and management of nature

preserves Importance of ecological restoration Importance of ecological restoration

Land Use in the World

Fig. 23-2p. 595

I. Land Use In The United States

A. PUBLIC LANDS(42%)- 35% of land in the United States is

designated as public and is managed by the Federal Government.

- Classified as…

1. Multiple-Use Lands 2. Moderately Restricted-use

Lands 3. Restricted-use Lands

U.S. Land Ownership

Federal35%

Private55%

Native American 3%

State and local 7%

National parks and preserves

National forests

National wildlife refuges

1. Multiple-Use LandsInclude… - 155 Forests and 20

Grasslands of the NATIONAL FOREST SYSTEM

- Managed by the U.S. FOREST SERVICE

and - NATIONAL RESOURCE

LANDS - Managed by the Bureau of Land Management

• 2. Moderately Restricted-Use Lands Include… - 522 NATIONAL WILDLIFE REFUGES

- Managed by the U.S. Fish and Wildlife Service

3. Restricted-Use LandsIncludes…the NATIONAL

PARK SYSTEM - 379 units of which

include 55 major parks and 324 national recreation areas.

- Managed by the National Park Service

and - 630 roadless areas of

the NATIONAL WILDERNESS PRESERVATION SYSTEM

Majority in Alaska

National parks and preserves National forests National wildlife refuges

How should the lands be managed?

Federal public lands contain valuable resources:• 20% of oil reserves• 30 % of natural gas• 40 % forest• large amounts of minerals

Conservation biologists point of view:

1. Protect biodiversity: habitats should be primary goal

2. No subsidies or tax breaks for using resources

3. Compensation for use of property

4. Take responsibility for any environmental damage

Developers point of view:

1. Sell public lands or their resources

2. Unregulate public lands

3. Replace old growth forests with tree plantations

4. Drill, mine, and commercially develop national parks

2 opposingviewpoints

23-2 Managing and Sustaining Forests(32% of earth land

surface)Ecological

Services

-Support food webs

-Act as sponge to absorb pollution

-Influence local climate

-Habitat

Economic Services

-Fuelwood, 50%

-Timber and Roundwood

-Pulp-Medicines

A. MAJOR TYPES OF FORESTS TROPICAL(47%) , subtropical(9%)

temperate(11%) , BOREAL/POLAR(33%)

B. CATEGORIES OF FORESTS…

1. OLD-GROWTH FOREST2. SECOND-GROWTH FOREST3. TREE PLANTATION

1. OLD-GROWTH FOREST

-FRONTIER FOREST

-Undisturbed by humans and/or natural disasters

-Very BIODIVERSE due to increased recycling of nutrients and good habitat

Emergent/Dominant

Canopy/Codominant

Understory/Intermediate

Floor/Suppressed

Subsoil

Layers of biodiversity

2. SECOND GROWTH FORESTS

Result from SECONDARY SUCCESSION as a result of human activities or natural disaster(s)

3. TREE PLANTATION or TREE FARMS

*An attempt to produce products more efficiently by setting back secondary succession.

*Often referred to as MONOCULTURE

*GROWS ONLY ONE SPECIES

*Harvested as soon as they become VALUABLE and then replanted.

C. TYPES OF FOREST MANAGEMENT- The total volume of wood produced by a

strand of forest VARIES as it goes through different STAGES of growth and succession

Time

Short rotation(pulp)

Wo

od

vo

lum

e o

r w

oo

d

bio

mas

s

B

C

A

Long rotations

Old-growth harvest(such as hardwoodsfor furniture)

Years of growth

30

25 1510

5

Clear cut

Weak treesremoved

Seedlingsplanted

- Two basic forest management techniques…

1. Even-Aged Management:

- Also called INDUSTRIAL FORESTRY - Trees are kept as same size and age

Ex: TREE FARM OR PLANTATION

*Extensive research has shown that soil become depleted

2. UnEven-Aged Management:

- Trees are kept at a variety of ages and sizes.

- -Goals are; biological diversity, long-term sustainable production of timber, moderate economical return, and multiple use of forests.

*The rate of economic return plays a major role in the technique used.

D. HARVESTING TECHNIQUES1. Selective Cutting: - Intermediate-aged or mature trees in an

uneven-aged forest are cut singly or in small groups

-reduces crowding -encourages growth -protects against soil erosion -maintains uneven growth

Selective Cutting

Selective Cutting: (continued)

-a special type of selective cut is used called…

high grading

-High Grading is when only the largest and best species are used.

2. Shelterwood Cutting:

-Removes all mature trees in two/three cuttings over a period of 10 years.

-allows natural regeneration -reduces soil erosion -provides good habitat for

wildlife

Shelterwood CuttingCut 1

Cut 2

3. Seedtree Cutting:

-Harvests nearly all a stand’s trees in one cutting, leaving a few seed-producing trees behind to regenerate the area.

-Leads to genetic improvement in

new stands

Seed-Tree Cutting

4. Clear Cutting:

-Removal of all trees from an area in a single cutting; either the whole stand, a strip, or a series of patches.

Clear-Cutting

PROS

- INCREASE YIELD- IMPROVES

STOCK- LESS SKILL

NEEDED- INCREASED $- BEST WAY TO

HARVEST TREE FARMS

CONS

- LEAVES LARGE OPENINGS IN FOREST

- REDUCES BIO- DIVERSITY

- INCREASES SOIL EROSION

- DECREASES RECREATION

5. Strip Cutting:

-Type of clear-cut that removes a strip of trees along the contour of the land, narrow enough to allow for natural regeneration

-Strips are harvested every 30-40 years

Strip Cutting

Uncut Cut Cut Cut Uncut

6–10 years ago3–5 years ago 1 year ago

F. FOREST SUSTAINABILITY HOW??-Longer rotation of timber growth-Emphasize selective cutting and

strip-Minimize fragmentation-Leave snags and down timber-Use proper anti-erosion

techniques

F. FOREST PESTS/DISEASE

1.Parasitic Fungi: accidentalchestnut blight (China)dutch elm (Asia)white pine blister (Europe)

2. Parasitic Insects:

Bark beetle

Gypsy moth

Hemlock woolly adelgid

G. FOREST AND FOREST FIRES - important part of ecological cycle of

some forests and grasslands

Types of Forest Fires:1. Surface Fires- burn leaf litter and

ground clutter

Surface fire Fig. 23.12a, p. 599

2. Crown fire- Burn in the treetops-most dangerous of all fires

Crown fire

3. Ground Fires- Underground and burn partially decayed or peat

-Common in pet bogs

H. Forest Fire Prevention:

-Fire prevention Techniques are a controversial subject

-Since 1972, the policy on forest fires has been to let them burn themselves out as long as not a danger to humans.

-After fires of 1994 and 2000, many calls for change.

Techniques Used-

*prevention*prescribed burning*pre-suppression*supression

23-3 Forest Resources/Management in

the US1. Today’s Status:

• Forest covers about 1/3 of the lower 48 United States.

• Forest are generally bigger and healthier than in 1920.

• Among most diverse in the world

National Forest Resources in US• 30% of US land, provides 80% of wildlife

habitats, supply 2/3 of all surface water runoff

• Economic benefits

-grazing lands, mineral resources, 3% of softwood timber

• Ecological benefits

-habitat for threatened/endangered species, clean drinking water

• Recreational benefits

- camping, hunting, fishing

• Since 1960, vast increase in the number of tree plantations – reduces biodiversity

• Between 1620-1998, most of existing old-growth forests in lower 48 states were cut

Virgin forests, 1620

Virgin forests, 1998

MANAGEMENT CONTROVERSY

Timber Companies

-Want to increase logging to satisfy demand…

-Improvement of forest health…

-Provides jobs…

-Provide cheap timber

Environmentalists

-Timber from national forest is small % of wood used

-Timber from national forests do little to drop prices

-Recreation use of forest should be most important use of forest

3. How To Reduce Tree Needs

- Increase the efficiency of wood use

- Increase paper recycling

-Use fibers that do not come from trees for paper (Kenaf)

23-4 Tropical Rainforest Deforestation and the Fuelwood Crisis

• They cover 6% of Earth’s land area• Brazil, Indonesia, Zaire, and Peru have more than half

of the world’s tropical forests• Over half of the world’s tropical forests have already

been cleared or degraded• Greatest destruction is taking place in South America

(Brazil)• Provide food products, ecological services, industrial

materials• Less than 1% of the plant species in the world’s tropical

forests have been examined closely for their possible use as human resources

Tropical deforestation is caused by:• Population growth• Poverty• Government policies

Forest Depletion and Degradation is caused by:• Commercial logging• Cattle ranching• Unsustainable form of farming• Replacing forest with cash crops• Increasing forest fires• Mining• Dams

Solutions: Reducing deforestation and degradation• Education programs – learn sustainable practices• Make it profitable to protect forests (debt-for-nature

swaps, conservation easements, and conservation concessions

• Carefully harvesting trees• National and global efforts to reforest and rehabilitate

degraded forests and watersheds• Reducing waste and consumption of timber, paper, and

other resources• Planting more fast-growing fuelwood trees or shrubs• Burning wood more efficiently• Switching to other fuels

Fuelwood Crisis• Fuelwood provides 7% of the world’s energy supply• Most common use of trees is for fuelwood.• Used for heat and cooking accounts for 80% of the

wood harvested in developing countries• 2.7 billion people did not get enough fuelwood to meet

their basic needs and were forced to meet their needs by using wood faster than it is replenished.

• Burn charcoal instead (uses twice as much wood)

23-5 Managing and Sustaining National Parks

• 1,100 parks• First national park system was created in the U.S.• In developed countries, parks are threatened by air and

water pollution, invasion of alien species, roads and noise

• Biggest problem of US parks is increased number of park visitors

• Currently, the greatest danger to the national parks is human activities (mining, logging, grazing, coal-burning plants, dams, urban development)

23-6 Establishing, Designing and Managing Nature Reserves

• Principals used to establish and manage reserves:

1. ecosystems are rarely stable

2. Ecosystems and communities that experience disturbances have the greatest diversity of species (intermediate disturbance hypothesis)

3. View reserves as habitat islands surrounded by a sea of developed and fragmented land

4. Include local people in the planning and design

5. Create use-friendly reserves that allow sustainable logging, grazing, crops, hunting, and fishing.

Wilderness

• Reasons to protect wilderness are:

1. Preserve biodiversity

2. Centers for evolution

3. Provide undisturbed habitats

4. Protect diverse biomes from damage

5. Provides a natural laboratory

Wilderness management• Designate camping sites• Limit the number of people using sites• Use volunteers to collect trash

What is Ecological Restoration?

1. Restoration ecology- Research and scientific study devoted to restoring, repairing, and reconstructing damaged ecosystems

Rehabilitation and RestorationAlmost every place on the earth has been degraded to

some degree by humans• Methods 1. Restoration-problems include lack of knowledge about

the system, changes in climate, and ecosystem are naturally changeing.

2. Rehabilitation- examples include removing pollutants, replanting

3. Replacement-example: a productive pasture replaced by a degraded forest

4. Creating artificial ecosystem- wastewater treatment systems and artificial wetlands

Save a piece of country… and it does not matter in the slightest that only a few people every year will go into it. This is precisely its value…We simply need that wild country available to us, even if we never do more that drive to its edge and look in. For it can be a means of reassuring ourselves of our sanity as creatures, a part of the geography of hope.

Wallace Stegner