TRF 2010e the causes..

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The Disappearing Canopy
The Causes
© Oxford University Press 2009
What human activities
cause tropical
deforestation?
Agriculture
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Mining
Commercial logging
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Dam construction
What human activities cause deforestation
in tropical rainforests?
Agriculture
Commercial
logging
Mining
Dam construction
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What are the underlying causes of tropical
Tropical
People demand
rainforests
for
deforestation?
Population growth
Population
Population
increases
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more
provide
food,
land
timber,
and
resources
minerals,
for etc.
people.
Resources
Resourcesdemanded
demanded
( decrease / increase )
What are the underlying causes of tropical
deforestation?
Why is population growth high in
rainforested countries?
This is no official family
planning in Brazil As long as child mortality
Among Malays, Chinese and Indians
because of the influenceremains high, people will
lived in Malaysia, Malays tend to
of the Roman Catholic continue to have large
have more children in the family.
Church.
families.
Their ideal family
size is to have
more than four children.
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What are the underlying causes of tropical
deforestation?
Poverty
Many tropical countries
have a low level of
economic development.
The people areofpoor
Governments
poorand
receive little
countries
do education.
not have
enough capital for
Levels
of technology
and
economic
development.
productivity is low.
These countries are
usually heavily in debt.
People picking up waste in a landfill in
Cambodia
(Credit: Ng Kim Hung)
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What are the underlying causes of tropical
deforestation?
Provide subsidies to
Government policy
commercial farmers
Encourage migration of
people to the rainforests
Loose land tenure
laws enabling
developers to buy
land in the rainforest
Corruption
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Improve road network to
increase accessibility
Local governments are attracted
by loans given by international
loan agencies for financing
projects in exploiting rainforests
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Agriculture
A
Shifting cultivation
Shifting cultivation is mostly
practised by native peoples and
landless or poor peasants.
Shifting cultivators grow different
crops, such as maize, beans,
yams, bananas and pineapples.
Some grow tree crops such as
cocoa and coffee.
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Agriculture
A
Shifting cultivation
The cultivators
clear the site by
cutting and
burning the trees
(Credit: Mark Edwards/Still Pictures)
The cultivators
abandon the
existing plot and
move to a new (Credit: Yann Arthus-Bertrand/Corbis)
plot of land
The cleared plot is
cultivated for several
years until the soil
nutrients are used up
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Agriculture
A
Shifting cultivation
The
carrying
capacityof
of the
Major
characteristics
land
in tropical
rainforest is
shifting
cultivation:
low. Therefore, shifting
Subsistence, mainly for own
cultivation is considered a
consumption
sustainable practice.
small farm size
labour intensive
staple crop growing
Footage showing shifting
cultivation in western Africa
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Agriculture
A
Shifting cultivation
Rapid growth in
population
Growing more crops on
the same amount of land
Why has shifting
cultivation become
destructive to the
More landless peasants
tropical rainforest?
becoming shifting
cultivators in the
rainforest also cause
more destruction to the
rainforest
The cultivation cycle is shortened
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Agriculture
A
Shifting cultivation
The pros:
-It may be a suitable way to make use of the harsh
environment in the TRF, with the low level of
technology.
- The labour productivity is relatively high.
- The energy output (harvest) is high when
compared with the energy input.
i.e. a high energy ratio
- It causes little environmental damage, providing
that the fallow period is long enough (e.g. 20 yrs)
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Agriculture
A
Shifting cultivation
The cons:
-It increases loss of nutrients by burning of biomass,
leaching of bases and increased soil erosion.
-It degrades the primary forest (the climatic climax) to
secondary forest, resulted in lower density, lower
height, smaller biomass, lower species diversity and
more open structure.
-It can only support a very small population size, or
the exceeding population pressure may cause long
term ecological damages.
* Viscous cycle of soil depletion: poor harvest
frequent movement
shorter cultivation cycle
shortened fallow period
lower soil fertility …
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Agriculture
B
Plantations
Tropical rainforests are felled for growing cash crops:
Tree crop: rubber, oil palm, cocoa and coffee
Arable crop: sugar cane and soybean
Coffee plantation in Brazil
(Credit: Biosphoto/Gunther
Michel/Peter Arnold Inc.)
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Agriculture
B
Plantations
Location
Rubber / oil palm plantation: West Malaysia
Coffee plantation: Brazil
Cocoa plantation: West Africa & Caribbean areas
Banana plantation: Caribbean areas
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Agriculture
B
Plantations
Major characteristics of plantations:
carried out by large corporations
monoculture (single crop cultivation)
Commercial, exportoriented
large farm size
cash crop growing
(Credit: Fernando
Bueno/Getty Images)
Soybean plantation in Brazil
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Agriculture
B
Plantations
Economic development results in a large demand for
tropical cash crops.
This accelerates the destruction of the
tropical rainforest.
In recent years, more soybeans
have been grown in the
rainforest to satisfy the
increasing demand for biofuel.
(Credit: Fernando
Bueno/Getty Images)
Soybean plantation in Brazil
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Agriculture
B
Plantations
Reasons for destruction of the tropical rainforest:
-Deliberate introduction & cultivation of economically
desired species of tropical / subtropical plants
-Causing widespread replacement of the native &
natural flora (and fauna), modifications or
disturbance of the natural landscape.
-Artificial practices
e.g. permanent removal of natural vegetation,
improvement of drainage and soil,
application of chemicals
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Agriculture
C
Cattle ranching
Tropical rainforests are
cleared to provide
pastureland for cattle
ranching.
Major characteristics of
cattle ranching in tropical
rainforests:
commercial extensive
large farm size
mainly for export
Cattle ranching in Brazil
(Credit: Mark Edwards/Still Pictures)
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Agriculture
C
Cattle ranching
Location
Central America: at least 2/3 of the arable land is used
for cattle production
Amazon Basin: about 1/5 had been cleared for farming
and cattle ranching
* Brazil:
- the world’s largest exporter of beef since 2004
- cattle ranching accounted for 60% of forest loss
from 2000 to 2005
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Agriculture
C
Cattle ranching
Deforestation
spreads fast
Demand for beef
increases
Overgrazing occurs
Soil is exposed to
erosion
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Cattle ranchers
move on new sites
and cut trees for
creating
pastureland
Soil quality
deteriorates
Agriculture
C
Cattle ranching – the case of Brazil
Cheap and
extensive
Why
is the land supply
Amazon
rainforest so
forofcattle
Poorpopular
awareness
environmental
conservation
ranching?
Attractive price of Brazilian beef
Supported by local governments
Brazilian beef being free of
livestock diseases
Expansion of road network, i.e.
Trans-Amazonian Highway
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In Brazil, cattle ranching accounted
for 60% of forest loss from 2000
to 2005
Commercial logging
Most trees in the tropical
rainforests are
hardwoods. They are
quality raw materials for
construction purposes
and for making furniture,
e.g. Teak, Mahogany,
Brazilian Rosewood.
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Commercial logging
Location
Central & Western Africa
Thailand
Indonesia
The Amazon Basin, etc.
* They export large amount of tropical timbers, sawn
wood and plywood to the developed countries.
•The US & UK have been the main importers of
Mahogany.
•The vulnerable Brazilian Rosewood has been harvested
as a highly prized wood for decorative veneers, highquality furniture (e.g. musical instruments), resin & oil.
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Commercial logging
Logging in the rainforest
is destructive since ...
Logging activities are often
unchecked / greenwashed.
Clear-cutting is carried out.
Tools: elephants vs bulldozers,
caterpillar wheels, crane?
Trees are cut to provide
space and to build roads.
The roads built by the logging companies
provide access for other forest users.
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Commercial logging
Rate of logging accelerates in
tropical rainforests because of:
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Mining and oil and gas exploitation
Many rainforests are rich in mineral reserves, e.g.
bauxite, coal, tin, and oil and gas deposits, by open-cast,
strip and shaft mining methods.
Urucu oil and natural gas plant in the
Amazon
(Credit: Reuters/OTHK)
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Gold mining in the Amazon
(Credit: Reuters/OTHK)
Dam construction
Hydroelectric power (HEP) is generated in rainforested
countries to provide energy with plentiful water supply.
HEP is considered the
most reliable source of
energy in the
rainforested countries
because:
it rains every day in
the tropical rainforests;
high annual rainfall;
water never freezes.
The Itaipu Dam in the Amazon rainforest
(Credit: Reuters/OTHK)
How about the
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