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%.

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Relocation of Brazilian capital to Brasilia in the 1950’s.

Government policiesGovernment policies

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 seedsUse of fertisisersUse of pesticidesUse 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

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.

As deforestation lowers the quality of the soil, it prevents proper absorption and water retainment.

Rainforest landscape before Deforestation

Rainforest Landscapeafter Deforestation

Rainforest Destruction

• Deforestation is taking place as the trees are being cut down.

Stage B

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 timberValuable trees in the rainforestSpace needed for roads and settlementsLand needed for ranchingValuable minerals to mine

√

Loss of wildlife habitatEffects on the atmosphereRemoving trees causes soil erosionLocal tribes are moved out by forceThe 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.