Land Use: Forests and Grasslands. Fig. 10-4, p. 193 Support energy flow and chemical cycling Reduce...

Land Use:Land Use:Forests and GrasslandsForests and Grasslands

Fig. 10-4, p. 193

Support energy flow and chemical cycling

Reduce soil erosion

Absorb and release water

Purify water and air

Influence local and regional climate

Store atmospheric carbon

Provide numerous wildlife habitats

Forests

Natural Capital

Fuelwood

Lumber

Pulp to make paper

Mining

Livestock grazing

Recreation

Jobs

EconomicServices

EcologicalServices

Types of Types of ForestsForests

Old-growth forestOld-growth forest: uncut : uncut or regenerated forest that or regenerated forest that has not been seriously has not been seriously disturbed for several disturbed for several hundred years.hundred years. 22% of world’s forest.22% of world’s forest. Hosts many species with Hosts many species with

specialized niches.specialized niches. Russia, Canada, Brazil, Russia, Canada, Brazil,

Indonesia & Papau New Indonesia & Papau New Guinea contain ¾ of the Guinea contain ¾ of the worlds remaining old growth worlds remaining old growth forests forests

Types of ForestsTypes of Forests

Second-growth forestSecond-growth forest: a stand of trees : a stand of trees resulting from secondary succession. (63% of resulting from secondary succession. (63% of worlds forests)worlds forests)

Tree plantationTree plantation: planted stands of a particular : planted stands of a particular tree species. (5% of worlds forests)tree species. (5% of worlds forests) Produce about ¼ of worlds commercial woodProduce about ¼ of worlds commercial wood China, Russia, USA, India & Japan contain 2/3 of the China, Russia, USA, India & Japan contain 2/3 of the

worlds tree farmsworlds tree farms China has almost no original forest left it is all second or plantationsChina has almost no original forest left it is all second or plantations

Global Outlook: Global Outlook: Extent of DeforestationExtent of Deforestation

Human activities Human activities have reduced the have reduced the earth’s forest cover earth’s forest cover by as much as half.by as much as half.

Losses are Losses are concentrated in concentrated in developing developing countries.countries.

Figure 10-7Figure 10-7

DeforestationDeforestation If current deforestation rates continue, it is If current deforestation rates continue, it is

estimated that 40% of the worlds remaining estimated that 40% of the worlds remaining forests will have been logged or converted to forests will have been logged or converted to other uses (human expansion) within 2 decadesother uses (human expansion) within 2 decades

Some temperate forests in North America, Some temperate forests in North America, Europe and China have seen an increase in area Europe and China have seen an increase in area since 1990’ssince 1990’s In the USA we are now seeing mor wood grown In the USA we are now seeing mor wood grown

every year than is cutevery year than is cut Some tropical rain forests have seen increasing Some tropical rain forests have seen increasing

secondary and tree plantationssecondary and tree plantations

Case Study: Deforestation and the Case Study: Deforestation and the Fuelwood CrisisFuelwood Crisis

Almost half the people in the developing Almost half the people in the developing world face a shortage of fuelwood and world face a shortage of fuelwood and charcoal.charcoal.

This is increasing cutting of forestsThis is increasing cutting of forests In Haiti, 98% of country is deforested.In Haiti, 98% of country is deforested. MIT scientist has found a way to make charcoal MIT scientist has found a way to make charcoal

from spent sugarcane.from spent sugarcane.

Cutting forests can also lead to soil erosion Cutting forests can also lead to soil erosion and sediment runoff into the water supplyand sediment runoff into the water supply

Forests can also be damaged by fire, pests Forests can also be damaged by fire, pests and disease (see supplement 15 in back of and disease (see supplement 15 in back of book)book)

Types and Effects of Forest FiresTypes and Effects of Forest Fires Depending on their intensity, fires can benefit or Depending on their intensity, fires can benefit or

harm forests.harm forests. Surface FiresSurface Fires

Burn away flammable ground material.Burn away flammable ground material. Release valuable mineral/nutrients into soil, control Release valuable mineral/nutrients into soil, control

pathogens and insects, stimulate germination, help pathogens and insects, stimulate germination, help prevent more destructive fires.prevent more destructive fires.

Crown FiresCrown Fires Extremely hot and rapid. Destroy most vegetation, Extremely hot and rapid. Destroy most vegetation, kill wildlife and increase soil erosion.kill wildlife and increase soil erosion.

Ground FiresGround Fires Surface fires that are burning underground. Can smolder Surface fires that are burning underground. Can smolder

for days or weeks. They are difficult to detect and for days or weeks. They are difficult to detect and extinguish.extinguish.


Solutions: Solutions: Controversy Over Fire ManagementControversy Over Fire Management To reduce fire damage:To reduce fire damage:

Set controlled surface fires.Set controlled surface fires. Allow fires to burn on public lands if they don’t Allow fires to burn on public lands if they don’t

threaten life and property. threaten life and property. Clear small areas around property subject to fire.Clear small areas around property subject to fire.

Alternative: use goats to eat underbrush!Alternative: use goats to eat underbrush! Because of “Smokey the Bear” most people Because of “Smokey the Bear” most people

think all forest fires are bad.think all forest fires are bad.

Solutions: Solutions: Controversy Over Fire ManagementControversy Over Fire Management In 2003, U.S. Congress passed the In 2003, U.S. Congress passed the Healthy Healthy

Forest Restoration ActForest Restoration Act:: Allows timber companies to cut medium and Allows timber companies to cut medium and

large trees in 71% of the national forests.large trees in 71% of the national forests. In return, must clear away smaller, more fire-In return, must clear away smaller, more fire-

prone trees and underbrush.prone trees and underbrush. Some forest scientists believe this could increase Some forest scientists believe this could increase

severe fires by removing fire resistant trees and severe fires by removing fire resistant trees and leaving highly flammable slash.leaving highly flammable slash.

Harvesting TreesHarvesting Trees

Building roads into previously inaccessible Building roads into previously inaccessible forests paves the way for fragmentation forests paves the way for fragmentation (breaking up habitat), destruction, and (breaking up habitat), destruction, and degradation (damaging habitat).degradation (damaging habitat).



Trees can be harvested Trees can be harvested individually from diverse individually from diverse forests (selective cutting), forests (selective cutting), an entire forest can be cut an entire forest can be cut down (clear cutting), or down (clear cutting), or portions of the forest is portions of the forest is harvested (e.g. strip harvested (e.g. strip cutting).cutting).



Effects of clear-cutting in the Effects of clear-cutting in the state of Washington, U.S.state of Washington, U.S.

Figures 10-10 and 10-11Figures 10-10 and 10-11

SolutionsSolutions

We can use forests We can use forests more sustainably by more sustainably by emphasizing:emphasizing: Economic value of Economic value of

ecological services.ecological services. Harvesting trees no Harvesting trees no

faster than they are faster than they are replenished.replenished.

Protecting old-growth Protecting old-growth and vulnerable areas.and vulnerable areas.


Controversy over Logging in U.S. National Controversy over Logging in U.S. National ForestsForests

There has been an There has been an ongoing debate over ongoing debate over whether U.S. whether U.S. national forests national forests should be primarily should be primarily for:for: Timber.Timber. Ecological services.Ecological services. Recreation.Recreation. Mix of these uses.Mix of these uses.


Solutions: Solutions: Reducing Demand for Harvest TreesReducing Demand for Harvest Trees

Tree harvesting can Tree harvesting can be reduced by be reduced by wasting less wood wasting less wood and making paper and making paper and charcoal fuel and charcoal fuel from fibers that do from fibers that do not come from trees.not come from trees. Kenaf is a promising Kenaf is a promising

plant for paper plant for paper production.production.


American Forests in a Globalized American Forests in a Globalized EconomyEconomy

Timber from tree plantations in temperate Timber from tree plantations in temperate and tropical countries is decreasing the need and tropical countries is decreasing the need for timber production in the U.S.for timber production in the U.S. This could help preserve the biodiversity in the This could help preserve the biodiversity in the

U.S. by decreasing pressure to clear-cut old-U.S. by decreasing pressure to clear-cut old-growth and second-growth forests.growth and second-growth forests.

This may lead to private land owners to sell less This may lead to private land owners to sell less profitable land to developers.profitable land to developers.

Forest management policy will play a key role.Forest management policy will play a key role.

CASE STUDY: TROPICAL CASE STUDY: TROPICAL DEFORESTATIONDEFORESTATION

Large areas of ecologically and Large areas of ecologically and economically important tropical forests are economically important tropical forests are being cleared and degraded at a fast rate.being cleared and degraded at a fast rate.


CASE STUDY: TROPICAL CASE STUDY: TROPICAL DEFORESTATIONDEFORESTATION

At least half of the At least half of the world’s terrestrial plant world’s terrestrial plant and animal species live and animal species live in tropical rain forests.in tropical rain forests.

Large areas of tropical Large areas of tropical forest are burned to forest are burned to make way for cattle make way for cattle ranches and crops.ranches and crops.


It is estimated that ½ of the worlds remaining It is estimated that ½ of the worlds remaining TRF’s could be lost or degraded in as few as TRF’s could be lost or degraded in as few as 35 years35 years

Less than 5% of the worlds TRF’s are Less than 5% of the worlds TRF’s are managed sustainablymanaged sustainably

Remember, TRF soil is low in nutrients so if the Remember, TRF soil is low in nutrients so if the forest is removed for agriculture purposes, the forest is removed for agriculture purposes, the soil can’t support many crops for many yearssoil can’t support many crops for many years

Many TRF’s are being turned into trpical Many TRF’s are being turned into trpical grasslands (savannas)grasslands (savannas)

Why Should We Care about the Loss Why Should We Care about the Loss of Tropical Forests?of Tropical Forests?

About 2,100 of the 3,000 plants identified by About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of the National Cancer Institute as sources of cancer-fighting chemicals come from tropical cancer-fighting chemicals come from tropical forests.forests.

Not to mention the global carbon cycle and global warming

Causes of Tropical Deforestation and Causes of Tropical Deforestation and DegradationDegradation

Tropical Tropical deforestation deforestation results from a results from a number of number of interconnected interconnected primary and primary and secondary causes.secondary causes.


Fig. 10-20, p. 207

Protect most diverse and endangered areas

Educate settlers about sustainable agriculture and forestry

Phase out subsidies that encourage unsustainable forest use

Add subsidies that encourage sustainable forest use

Protect forests with debt-for-nature swaps and conservation easements

Certify sustainably grown timber

Reduce illegal cutting

Reduce poverty

Slow population growth

Restoration

Reforestation

Rehabilitation of degraded areas

Concentrate farming and ranching on already-cleared areas

Solutions

Sustaining Tropical Forests

Prevention

How can we help the worlds forests?How can we help the worlds forests? Have community forest projects (ex. next Have community forest projects (ex. next

slide) to help replant forestsslide) to help replant forests Reduce our use of wood products, find Reduce our use of wood products, find

alternative sources (ex. new ways to make alternative sources (ex. new ways to make paper, solar ovens instead of charcoal, more paper, solar ovens instead of charcoal, more efficient/less polluting wood stoves)efficient/less polluting wood stoves)

Don’t waste as many wood productsDon’t waste as many wood products It is estimated that 60% of wood products used in It is estimated that 60% of wood products used in

the USA are wastedthe USA are wasted Just think of all of the paper we used and disposed of Just think of all of the paper we used and disposed of

today (including tissues, paper towels, etc)today (including tissues, paper towels, etc)

Kenya’s Green Belt Movement:Kenya’s Green Belt Movement:Individuals MatterIndividuals Matter

Wangari Maathai Wangari Maathai founded the Green Belt founded the Green Belt Movement.Movement.

The main goal is to The main goal is to organize poor women to organize poor women to plant (for fuelwood) and plant (for fuelwood) and protect millions of trees.protect millions of trees.

In 2004, awarded Nobel In 2004, awarded Nobel peace prize.peace prize.

Figure 10-10AFigure 10-10A

MANAGING AND SUSTAINING MANAGING AND SUSTAINING GRASSLANDSGRASSLANDS

Almost half of the world’s livestock graze on Almost half of the world’s livestock graze on natural grasslands (rangelands) and natural grasslands (rangelands) and managed grasslands (pastures).managed grasslands (pastures).

We can sustain rangeland productivity by We can sustain rangeland productivity by controlling the number and distribution of controlling the number and distribution of livestock and by restoring degraded livestock and by restoring degraded rangeland.rangeland.


Overgrazing occurs when too many animals Overgrazing occurs when too many animals graze for too long and exceed carrying graze for too long and exceed carrying capacity of a grassland area.capacity of a grassland area.

This can lead to increased soil erosion and This can lead to increased soil erosion and invading (not invasive) speciesinvading (not invasive) species



Example of restored area along the San Example of restored area along the San Pedro River in Arizona after 10 years of Pedro River in Arizona after 10 years of banning grazing and off-road vehicles.banning grazing and off-road vehicles.


SuggestionsSuggestions

Rotational grazingRotational grazing Ban grazing near rivers and streamsBan grazing near rivers and streams Replanting native grasses and removing Replanting native grasses and removing

“invader” species like mesquite, cacti and “invader” species like mesquite, cacti and sagebrush (which livestock don’t eat anyway)sagebrush (which livestock don’t eat anyway) Use herbicides (may lead to other problems)Use herbicides (may lead to other problems) Let livestock trample themLet livestock trample them Manually remove Manually remove

Apply fertilizers (may lead to other problems)Apply fertilizers (may lead to other problems)

NATIONAL PARKSNATIONAL PARKS

Countries have established more than 1,100 Countries have established more than 1,100 national parks, but most are threatened by national parks, but most are threatened by human activities.human activities. Local people invade park for wood, cropland, Local people invade park for wood, cropland,

and other natural resources.and other natural resources. Loggers, miners, and wildlife poachers also Loggers, miners, and wildlife poachers also

deplete natural resources.deplete natural resources. Many are too small to sustain large-animal Many are too small to sustain large-animal

species.species. Many suffer from invasive species.Many suffer from invasive species.

NATURE RESERVESNATURE RESERVES

Wilderness is land legally set aside in a large Wilderness is land legally set aside in a large enough area to prevent or minimize harm enough area to prevent or minimize harm from human activities.from human activities.

Only a small percentage of the land area of Only a small percentage of the land area of the United States has been protected as the United States has been protected as wilderness.wilderness.


Ecologists call for protecting more land to Ecologists call for protecting more land to help sustain biodiversity, but powerful help sustain biodiversity, but powerful economic and political interests oppose doing economic and political interests oppose doing this.this. Currently 12% of earth’s land area is protected.Currently 12% of earth’s land area is protected. Only 5% is strictly protected from harmful human Only 5% is strictly protected from harmful human

activities.activities. Conservation biologists call for full protection of Conservation biologists call for full protection of

at least 20% of earth’s land area representing at least 20% of earth’s land area representing multiple examples of all biomes.multiple examples of all biomes.


A model biosphere A model biosphere reserve that reserve that contains a protected contains a protected inner core inner core surrounded by two surrounded by two buffer zones that buffer zones that people can use for people can use for multiple use.multiple use.



Geographic Information System (GIS) Geographic Information System (GIS) mapping can be used to understand and mapping can be used to understand and manage ecosystems.manage ecosystems. Identify areas to establish and connect nature Identify areas to establish and connect nature

reserves in large ecoregions to prevent reserves in large ecoregions to prevent fragmentation.fragmentation.

Developers can use GIS to design housing Developers can use GIS to design housing developments with the least environmental developments with the least environmental impact.impact.


We can prevent or slow down losses of We can prevent or slow down losses of biodiversity by concentrating efforts on biodiversity by concentrating efforts on protecting global hot spots where significant protecting global hot spots where significant biodiversity is under immediate threat.biodiversity is under immediate threat.

Conservation biologists are helping people in Conservation biologists are helping people in communities find ways to sustain local communities find ways to sustain local biodiversity while providing local economic biodiversity while providing local economic income.income.

34 hotspots identified by ecologists as important and 34 hotspots identified by ecologists as important and endangered centers of biodiversity.endangered centers of biodiversity.


ECOLOGICAL RESTORATIONECOLOGICAL RESTORATION

RestorationRestoration: trying to return to a condition as : trying to return to a condition as similar as possible to original state.similar as possible to original state.

RehabilitationRehabilitation: attempting to turn a : attempting to turn a degraded ecosystem back to being degraded ecosystem back to being functional.functional.

ReplacementReplacement: replacing a degraded : replacing a degraded ecosystem with another type of ecosystem.ecosystem with another type of ecosystem.

Creating artificial ecosystemsCreating artificial ecosystems: such as : such as artificial wetlands for flood reduction and artificial wetlands for flood reduction and sewage treatment.sewage treatment.

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