People in the Tropical Rainforest
S4
Standard Grade
The Amazon Rainforest
Can It Survive ?
Will it Survive ?
Peoples’ Use of the Environment
• Describe the use of this environment by the
native inhabitants (i.e. before development).
• Describe and quote examples of a range of
present day uses of this environment.
Peoples use of the Environment
Uses of the rainforest include:• 1.
logging the valuable timber resources
• 2.
mining the valuable minerals which lie beneath this largely
unexploited area
e.g. oil and metallic ores
• 3.
farming a.
by native inhabitants i.e. ‘slash + burn’
cultivation
•
b.
by migrants from the overcrowded towns.
These people tend to clear and cultivate small
plots of land beside the lumber roads. Their
impact is large as they arrive in their thousands.
•
c.
by large cattle ranches. These clear thousands
of hectares using bulldozers or firebombs and
plant the land in grass.
• 4.
increasing discovery of medicinal uses of many plants in the
forest.
•
•
•
•
Tropical rain forests are full of life. Not only do millions of
plants and animals live here, but many people also call the rain
forests home.
Indigenous, or native, people have lived in the rain forests for
thousands of years.
Native tribes of the rain forest have their own traditions and
languages. They have learned how to use plants to treat many
illnesses.
All indigenous people share strong ties to the land. The rain
forest is so important for their culture, so they want to take
care of it.
Native People of the Rainforest
For centuries, the Rainforest has been used as a home
for many different cultures and tribes.
The native people of the rainforest do not live in houses
like ours. They have a different lifestyle to our own.
Slash and Burn
• Shifting cultivation – how it is practiced
– Small patches of land are cleared by chopping
vegetation and girdling trees
– When vegetation has dried, it is burned
– These techniques give shifting agriculture the
name “slash-and-burn”
– With digging sticks or hoes, farmers plant a
variety of crops in the clearings
Amazon Basin
Slash and burn clearings
Note that these are often found beside rivers.
Why do you think they are found there ?
Subsistence Agriculture 1
• Subsistence agriculture—involves food production
mainly for the family and local community rather
than for market
• Farmers keep few if any livestock, often relying on
hunting and fishing for much of their food supply
• Has proved an efficient adaptive strategy
• Slash-and-burn farming may return more calories of
food for the calories spent than modern mechanized
agriculture
• Has achieved sustainability for millennia in the
absence of a population explosion
Subsistence Agriculture 2
• How it is practiced
– Intertillage—the practice of planting taller,
stronger crops to shelter lower, fragile ones
from tropical downpours
– Intertillage reveals a learning acquired over
many centuries
– Little tending of the plants is necessary until
harvest time
– No fertilizer is applied to the fields
– The same clearings may be planted for four or
five years until the soil loses it fertility
– New fields are prepared and old fields may be
abandoned for 10 to 20 years
•
•
•
Little, by little, people are destroying the
rain forests. They cut down trees for
lumber and clear them away to provide land
to grow crops on.
Rain forests once covered an area almost
twice the size of the continental United
States. Today, only half of the rain forests
remain.
People all over the world must work together
to save the beautiful, unique rain forests
before it is too late.
The Amazon is being destroyed
• The Amazon’s
resources are being
exploited by huge
corporations
• Deforestation is
destroying hundreds of
hectares of rainforest
every day.
What is deforestation
Deforestation is the
cutting down of trees.
Why do we do this ?
• Slash and burn farming
• New ranchlands.
• To build new roads and
settlements
• To harvest tropical
hardwoods
• To mine minerals
Causes of Deforestation
Tropical forests are destroyed
for several reasons.
There is and increasing demand
for both farm and grazing land,
which results in the burning
and clearing of rain forests for
agriculture production.
Another cause of deforestation
is the continued the world need
for timber for furniture and
building.
How does deforestation effect
us?
Deforestation effect us
when we cut down the
trees we got less oxygen.
Burning of the forest
increases the amount of
carbon dioxide in the
atmosphere and this
increase is contributing to
global warming.
How much rainforest is left ?
All of the rainforests combined
cover an astounding 5.5 billion
acres of land worldwide.
Unfortunately, they are being
destroyed by an average of 70
hectares a day. At this rate, the
rainforests will be completed
destroyed in 40 years. These
diverse but delicate ecosystems are
said to hold over fifty percent of all
plant and animal species on Earth,
but sadly may see the extinction of
5 to 100 of these species a year. We
have already seen mass destruction
of the rainforests in the last 60
years. What used to make up15%
of the Earth's land, now only
comprises 7%.
.
Government policies
 Relocation of Brazilian capital to Brasilia in the
1950’s.
 Construction of highways to integrate country.
• Bélem-Brasília, Cuiába-Santarém, Transamazon
highways, Northen Perimeter Road.
Encouragement of large scale entrepreneurs to
“develop” the Amazon after 1973 oil crisis.
• Tax policies that facilitate clearance of land.
• Amazon Development Agency, Amazon Development
Bank. and Amazon agencies
Timber activities.
Commercial Logging
The exportation of timber provides a
major source of income.
 The damage caused by logging is extensive and the
timber industry can be held responsible for at least 40%
of deforestation.

Although the government has a policy that requires
loggers to replant the areas they deforest, many do
not follow this practice.

The
loss of biodiversity, the extinction of many
species and the increased number of floods that have
resulted from logging are not worth the little profit that
is received.
Cattle Ranching
Much of the land being cleared is used for cattle
ranching.
 Forest is being converted to pasture for these
ranchers at a rate of about 35,000 square
kilometers per year.
 Ranches are not very economic and ranchers
hardly ever make a profit off of the livestock.
 What makes this scheme so profitable is the land
speculation associated with it.

One of the current policies states that anyone who
clears an area of land can lay claim to it, and cattle
require large tracts of land. The mineral rights below
this land are also owned by the person who clears it.

Cash Crop Plantations

Those used for Industrial Forestry and Export Crops
are major Causes of deforestations.
Those that are dominant in the Amazon region are
of rice and sugar cane.

The profits made from these plantations are not
used to support the inhabitants of the Amazon, so
they are forced to utilize more of the land to support
their families.

This results in an increase in the degradation of
the land and a declining resource base.

Causes of Deforestation of the Rainforest
Annual Destruction of Tropical Forests
in the World
(millions of hectares)
Slash and Burn
9
Cattle Ranching
1.5
Commercial Farming
1.5
Tree Plantations
1.3
Logging
6
Mining
0.1
Total
19.4
Source: World Rainforest Movement
What does the Rainforest have to
offer me?
We should be concerned about the Amazon
rainforest because...
the rainforest gives us...
•
•
•
•
food products
exotic animals
indiginous people
medicinal plants
Indigenous Peoples
• Native peoples
have unique
cultures and
languages which
are threatened by
Amazon
exploitation
Medicinal Plants
• Potentially, cures
for many
devastating
diseases may be
found in the
rainforest flora.
Unique Animal Species
• Many native
Amazon species
exist nowhere
else on earth
Time is running out
• Once these unique and precious resources
are gone, they can never be replaced.
Experts suggest changing from
slash & burn land use to
sustainable development
This can be achieved by :Better plant seeds
Use of fertisisers
Use of pesticides
Use of weedkillers.
Do we really want this ?
How do we do this?
• Educate the local people
• Educate globally
What Else Can We Do ?
• Reduce our use of tropical hardwoods.
• Reduce our use of cattle products from
ranches in the tropical rainforest.
Any Suggestions on How We
Can Reduce :• Timber exploitation ?
• Cattle products from ranches in the tropical
rainforest ?
Peoples’ Abuse of this
Environment
• Give a range of examples of how use /
exploitation of this environment has led to
damage to the environment.
Peoples abuse of the environment
•
•
If the forest is damaged, e.g. by fire, it can naturally regenerate but
where people destroy thousands of hectares and attempt to farm this
land a number of problems may occur which leave the land of little use.
Soil erosion, with the heavy rain, can strip the bare land of its essential
soil or the hot sun can bake the land as hard as concrete.
The rainforest is essential as a home for insects + plants (50% + of the
planets plants + animal species live here). Many of the plants are
valuable sources of medicines + drugs (many yet undiscovered). It
also provides us with a valuable source of oxygen, without which CO2
would increase with resultant global warming. It is also the home of
native people whose lives and lifestyles are being destroyed.
Why shouldn’t we cut
down rainforests?
• Rainforests - very high diversity of animal and
plant life (lots of different kinds)
• Very difficult to replace - not many nutrients in
the soil so once the plants are gone it is hard to
grow any plants in that area
• Add oxygen to the atmosphere (40%)
but also use much oxygen by decay
Long-Term Consequences of Deforestation


Increased loss of biological diversity of
many plant and animal species
Destruction of forest based societies
Increasing numbers of:
–Floods
–Droughts
–Soil Erosion Problems
 Depletion of the forest canopy which
protects against high winds and soil
erosion

Ecological Concerns 1 : Erosion
The soil underlying the plants and vegetation on the
floor of the rainforest is generally poor due to most of the
nutrients being tied up in the vegetation.
 As the forest is cut down, the nutrients are washed out of
the soil, and eventually transfers this area into a wasteland
stripped of everything but unpalatable grasses.
 These soils are covered with ironstone which is rapidly
leached out of the soil when exposed to direct rainfall.

This ironstone becomes oxidized and is converted into a
hard, brick-like substance which is impossible to grow
anything on.

If this process continues, these rich forests will be
turned into a field of unworkable rock with no profits
being generated at all.

Ecological Concerns 2 : Floods

One of the most important functions of the rainforest is
to control rain water.
The continuous clearing of forest land increases
surface runoff because a large proportion of the water
reaches the surface and is not caught by the trees.

The
soil is not able to absorb the large amounts of
water due to soil compaction on the surface.
 Therefore the water runs directly to local streams
and rivers which causes them to flood.
Ecological Concerns 3 :Droughts
As deforestation lowers the quality of the
soil, it prevents proper absorption and water
retainment.
There is a continuous ‘drought-flood’ cycle,
which consists of massive floods during
monsoon periods of rain and devastating
droughts during the dry seasons.

This water is then not allowed to travel to local
streams and rivers to replenish them, and
eventually drying them up.

Rainforest landscape
before Deforestation
Rainforest Landscape
after Deforestation
Rainforest Destruction
Stage B
• Deforestation is taking place as the trees are
being cut down.
Q1a
Stage D
• Soil erosion is taking place as the sun bakes
the soil and the rain washes away the
topsoil forming gullies.
√
Need for timber
Valuable trees in the rainforest
Space needed for roads and settlements
Land needed for ranching
Valuable minerals to mine
√
Loss of wildlife habitat
Effects on the atmosphere
Removing trees causes soil erosion
Local tribes are moved out by force
The soil quickly loses its fertility
Another Viewpoint
There has been much concern by
environmentalists about the loss of forests in the
Amazon area.
A survey in 1996, however,suggested only 12%
of the Amazon was considered to be changed
significantly.