1 global connections: forests of the world activity 4 analyzing patterns of forest change

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Global Connections:

Forests of the World

Activity 4

Analyzing Patterns of Forest Change

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Objectives

Identify global trends in a forest area.

Analyze maps of a particular forest to determine how and why its shape and size have changed over time.

Examine how people affect forest changes.

Investigate and present the reasons behind changes in a forest area observed in your own community or in another country.

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Searchable Key Words

afforestation deforestation environmental change environmental history forest clearing forest cover change map forest history landscape history long-term ecological site plantation forest reforestation

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Background

Activity 4

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Major factors determining the type and extent of forests

1. latitude2. climate3. terrain of a particular location4. altitude 5. type of soil6. soil drainage or lack thereof7. fire intensity and frequency8. history of glaciers9. tree species that originated or were able to disperse to

that area10. disease or insects11. frequency of hurricanes, earth quakes, volcanoes,

mudslides, and other natural disturbances 12. humans

Activity 4 – Background

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Fossil evidence suggests that hunter-gatherers living on the margins of forested land used fire to

influence the mix of trees, shrubs, and grasses—perhaps to attract game or to make it easier to

travel through the landscape


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As humans began to raise sheep, goats, and other herd animals, they used fire to encourage the

growth of new green grass shoots for their herds to graze.


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Scientists offer varied estimates of how much the world’s forest cover has been reduced by human activity

throughout the past several millennia.

Those estimates put today’s forest cover at between 50 and 80 percent of what it might be without human activities


Example:

Image: http://www.fs.fed.us/ne/delaware/biotrends/trends22.JPG

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Three main human pressures on forests

deforestation

forest fires

and fragmentation


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Deforestation

Reasons: Loss of forest land, usually from development, urbanization, conversion to agriculture, flooding land for hydroelectric development…

Conditions such as poverty, joblessness, and an unequal distribution of land lead to deforestation. These conditions force landless farmers to clear forests for farming or grazing because they have no other way to make a living.

Other activities indirectly lead to deforestation, including warfare, pollution, and human-caused global climate change.

Definition: the permanent removal of trees from a forested area


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Forest fires

The number and intensity of human-caused forest fires greatly exceeds naturally occurring fires

Can cause significant damage even to those forest ecosystems that are adapted to a fire regime.

Routine fires set to burn debris, to clear fields, to clear underbrush to reduce fire potential near forested areas can escape control and cause extensive forest damage.

Routine fires are an increasing source of destruction in tropical moist forests

Example: In the 1980s, and into the late 1990s, human-caused fires in Indonesia caused massive environmental and economic damage not only within that country, but also in neighboring countries such as Malaysia and Singapore, where the smoke led to health problems, disruption of shipping, and international airports being closed


Definition: natural or human-caused disturbance that affect forest.

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Fragmentation

• This fragmentation diminishes species diversity because it creates different habitat conditions along the edges of the smaller blocks.

• Example: there may be less moisture and more sunlight and wind near the edges, making it hard for certain plant and animal species to survive and more difficult for animals to find food or shelter. Fragmentation may also block migration routes and open new areas for invasion by nonnative species. In addition, roads provide easier access into the forest for hunting, wood gathering, land clearing, and other activities that alter the forest ecosystem.


Definition: division of a large or continuous forest into smaller blocks, either by roads, clearing for agriculture, urbanization, or other human development.

13Image: http://www.wettropics.gov.au/st/rainforest_explorer/Library/ImageLibrary/Development/Developmentindex_2.htm

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Trying to increase forests

Reforestation Afforestation


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Reforestation

Humans may plant trees to increase forests.

People may decide to reforest an area for commercial purposes, such as a plantation for forest products, or they may want to reestablish the natural forest environment for recreation or noncommercial purposes.

Example: The Tijuca Forest in Rio de Janeiro, Brazil, is the largest urban forest in the world and was reforested in the 1800s when erosion threatened the city after the forest was cut for coffee plantations.

Definition: renewing forest cover on a cut or burned forest area by seeding or planting


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Tijuca Forest, Rio de Janeiro, Brazil

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Afforestation

Afforestation usually requires major human intervention and management.

Example: Uruguay is one country that has an extensive afforestation program. With the goal of replacing unprofitable farming and livestock grazing on poor soils with profitable forests, those afforested plantations provide timber, pulpwood (for paper), and fuelwood.

Definition: the planting of trees to create a forest on lands that were not historically forest


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Doing the activity

Activity 4

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Now, time to work!

Part A:The Duke Forest

Activity 4 – Doing the activity

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1. Discussion

a. How have forests in our state changed over time?

b. How do you think the extent of forests around the world have changed over time?

c. Where is forest cover changing the most?

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2. What factors might have influenced these changes in the world’s forest area?

Which factors are forces of nature?

• ______________• ______________• ______________• ______________

Which factors are human forces?

• ______________• ______________• ______________• ______________

a.Which forces do you think have the biggest influence on forests today?

b.How about in the past or the future?


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3. In groups of 3 or 4, look at the cards and discuss…

a. What are the main ways that humans change forests?

b. How does each of those ways influence the extent of forests?


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4. Let’s look closely at one forest…

Material:

1. “One Forest Over Time”

2. “Map Analysis Tool”


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a. What are the differences and similarities between them (size and shape of the forest)?


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b. Trace the map onto the “Map Analysis Tools” Activity 4 – Doing the activity

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5. In small groups…

1. Discuss the causes of the changes2. Read the “From Forest to Farm to Urban

Forest” (student page)3. Discuss the questions:

a. What factors influenced the size of this forest over time?

b. What factors have influenced its extent and location?

c. Do you think those factors are similar to what might be found in other places on Earth? Why or why not?


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Part B:

Change over time


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1. Let’s check this interview…

“Planting Trees in Kenya”

http://www.pbs.org/newshour/bb/environment/jan-june05/maathai_1-25.html

Discussion:

What are the benefits of planting trees in Kenya and the challenges or barriers that Maathai and other Kenyans have faced?




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2. Challenge

Search records on forest cover change in your own community or in another country to find out:

a. what changes have occurred over time,

b. the causes of the changes,

c. whether anything is being done or could be done to slow or reverse the changes,

d. what people in the community have been agents of change, and

e. what students can do to effect changes.


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Potential information sources:

• Aerial photographs or satellite images from the local planning department.

• Maps of forest cover from the local forestry agency.• GIS (geographic information systems) digital data.

http://www.gis.com, http:// www.esri.com, • The Food and Agriculture Organization (FAO) of the

United Nations (check the TEMS - Terrestrial Ecosystems Monitoring Sites - database at http://www.fao.org).

• Maps, photos, or logs housed at the local historical society.


http://www.gis.com/

http://www.esri.com/

http://www.fao.org/

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3. Discuss…

…whether the factors involved in the changes are still issues and whether actions can or should be

taken to slow or reverse those changes.


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Assessment

1. Part A, write a paper describing first the observed differences in the Duke Forest over time and answer the questions:

a. What factors influenced the size of this forest over time?

b. What factors have influenced its extent and location?c. Do you think those factors are similar to what might

be found in other places on Earth? Why or why not?

Express your understanding of the various factors that play into the Duke Forest story: climate, family farming, Indian

management, research forestry, tobacco farming, and urban development.

2. Part B, student’s presentations

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Enrichment

Activity 4

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Research how forests have changed in your area over geologic time.

For example: where there is now a dry, cactus-studded

desert in central Arizona, 225 million years ago the area was a lush forest with conifer trees towering almost 200

feet tall. The area was once located near the equator and on the southwestern edge of the super-continent

“Pangea,” which broke up to create our present continents.

Forests change in your area over geologic time

Activity 4 – Enrichment 1

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Forest data in your state or region

Look for information about a forest in your state or region.

For example: Many states and universities have research forests similar to the one at Duke University. Harvard University has long-term data on its Harvard Forest (http://harvardforest.fas. harvard.edu).

Activity 4 – Enrichment 2

http://harvardforest.fas.harvard.edu/

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Technology

Explore how forests relate to the topic of biotechnology

What are the differences between traditional methods for modifying plants (such as selective breeding) and genetic modification?

a. How are forests affected when humans modify the DNA of trees to make them (a) adapted to local conditions, (b) more resistant to insects or disease, or (c) grow faster and bigger to meet the needs of the grow ing human population?

b. What trade-offs are involved?

As a place to start: Genetically Modified Trees: From Stone Age to Modern Biotechnology by Rowland D. Burdon and William J. Libby (Forestry History Society 2006).

Activity 4 – Enrichment - Technology

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Careers

Interview a local planner (or other person who uses maps and mapping in their job) to find how

mapping and other tools enhance the work being done in your community.

Activity 4 – Enrichment - Careers

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Resource

•America’s Ancient Forests: From the Ice Age to the Age of Discovery by Thomas M. Bonnicksen (New York: Wiley, 2000) •Deforesting the Earth: From Prehistory to Global Crisis by Michael Williams (Chicago: University of Chicago Press, 2002) •The Duke Forest at 75: A Resource for All Seasons by Ida Phillips Lynch (Durham, NC: Office of the Duke Forest, Duke University, 2006) •A Forest Journey: The Role of Wood in the Development of Civilization by John Perlin (Cambridge, MA: Harvard University Press, 1991) •The Last Forest: The Story of Hatfield Forest by Oliver Rackham (London: Weidenfeld and Nicholson, 1998)

1 global connections: forests of the world activity 4 analyzing patterns of forest change

Documents

forest area

particular forest

forest changes

forest ecosystems

loss of forest land

extensive forest damage

worlds forest cover

todays forest cover