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Manaus
Carajas
Paragominas
Rondonia
Matte Grosso
Brasilia
Amazonia Climate
•Hot and wet all year – 27 degrees Celsius average temperature.
•Rain all year, in excess of 250mm per month, annually up to 2000 mm.
•Small diurnal (daily) temperature range of 5-6 degrees
•convectional rainfall
•small annual temperature range (2-3 degrees)
•no seasons as a result of temperatures and rainfall.
Convectional
Rainfall
Sun heats
ground, ground
heats air, water
evaporates,
warm air rises,
as it rises it
cools,
condenses to
form clouds,
clouds become
saturated, it
rains.
High temperatures due to angle of the sun and latitude:
The earth’s axis is at 23.5 degrees, effecting the angle at which the sun’s rays strike the Earth.
At the equator, the sun is directly overhead twice every year, in March and September (equinoxes).
This means that the incoming rays of sunshine are concentrated over a smaller area, so more of
the sun’s energy reaches earth, rather than being lost when passing through the atmosphere.
This accounts for the high temperatures and low temperature range.
Cloud cover means that diurnal range of temperature is low.
The Amazon Rainforest
5 layers in the forest:
1.
Undergrowth – very little because there is little light
2.
Layer of shrubs and young trees
3.
Discontinuous under canopy of smaller and immature trees
4.
Continuous layer of the main canopy formed by crowns of many
tall trees
5.
Discontinuous canopy of tree crowns of the tallest trees, called
emergent trees.
Adaptations of Plants
Drip tip leaves – sheds water quickly so that leaves do not rot
Branchless tree trunks – trees save their energy to grow to be as
tall as possible to reach light.
Lianas – vine like plants climb the tree to reach the sunlight
Shallow roots – because all of the nutrients are found at the
surface of the soil
Little undergrowth – little light available makes it difficult to survive
Waxy cuticle (leaf surface) protects leaf from intense sunlight and
rain
Buttress Roots help to support the tall tree
Tall trees – grow to be as tall as they can to allow them to reach
maximum amount of sunlight.
Nutrient Cycle
Sunshine and rain help the
trees to grow. Trees contain
nutrients. Leaves fall to the
ground and rot, making
nutrient rich humus. Rain
washes nutrients from humus
into the soil. Nutrients are
contained in the soil, which
are absorbed by plant roots.
When trees are chopped own,
the nutrient cycle is broken,
which puts the forest in
danger.
Climate:
Hot throughout year, very high
precipitation, no seasons,
daily heavy rainfall
Leaching occurs – soil is
washed of nutrients
Vegetation:
Soils
Very dense evergreen forest,
huge biodiversity, constant
growing season
There is a constant layer of
material like leaves which
decompose adding to
nutrients in the soil
Soil is POOR
Soil is RICHER
Overall, soils are poor,
nutrients are washed
away by rain and drained
of nutrients by the huge
numbers of vegetation.
Agriculture
Shifting Cultivation – ‘Slash and Burn’
The indigenous Amerindian tribes such as the Yanomami practise this type of subsistence
agriculture. It is sustainable, as it works with the ecosystem.
A small area of forest is
cleared using
machetes, and when
the felled trees have
dried out, they are
burned. The ash
produced helps to
provide extra nutrients
for the soil.
Holes are made in the
ground, and cuttings and
seeds of crops like sweet
potatoes, cassava,
manioc and bananas are
planted. Hot wet climate
means crop grow quickly,
but must be weeded
regularly.
Crops are harvested. After 3 or 4 years, crop yields
decline as soils lose nutrients, and the tribe move to
another area, leaving this for 30 years to allow it to
recover.
Shifting cultivation pros: works with
ecosystem, sustainable, traditional,
does not harm biodiversity. Cons: low
yield, limited crops, supports only
small numbers of people.
Peasant Farming - Rondonia
Non-indigenous people who have arrived in the Amazon through
government encouragement. Many poor people from the East
of Brazil move land on the sides of roads. However, as more
forest is cleared, the soil loses nutrients and farmers’ yields
decline, and so they can no longer live off the land. This
results in most moving to the city to look for work.
Pros: new life, support form government, reduces
overpopulation elsewhere, improves accessibility. Cons:
Clears large areas of forest, soil is poor, so poor yield, will
not support people for long.
Cattle ranching – Mato Grosso
From 1970 onwards, many transnational
companies set up large ranches on
which to keep cattle to produce beef.
Each animal requires a large area of
land form grazing, and is provided by
cutting down trees in the forest. Soil
fertility rapidly reduces and grazing
becomes too poor for ranching.
Exploitation of the Forest: Case Studies
Paragominas – Logging
South of Belem, is the most extensively logged area of the Amazon, where illegal logging is a
problem.
Carajas – Mining
On the Tocantins River, 900km SW of Sau Luis, a deep water port, where open cast iron ore
mining takes place. Current excavations are 4.1 km long, 300m wide and 400m deep in 14m
high, step like benches.
Electricity supply from Tucurui HEP station
used for powering living quarters and
machinery
Belem Highway and Trans-Amazonian
Highway pass through Carajas.
900km rail corridor cleared holding 25 pig
iron smelters using charcoal. Producing the
charcoal deforests 6000km squared per
year.
2160km squared flooded to provide dam
with water.
Cattle ranching - Mato Grosso
Largest area of deforestation for cattle ranching. 1.5 cows supported per hectare, because
grass is so poor. 2 cowboys look after 1000 cows, so employment is low.
Carajas – Mining
On the Tocantins River, 900km SW of Sau Luis, a deep water port, where open cast iron ore
mining takes place. Current excavations are 4.1 km long, 300m wide and 400m deep in 14m
high, step like benches.
Effects of Exploitation
Use of the
forest
Effects on people
Effects on environment
Logging
Provides an alternative
source of employment,
improves accessibility
into the forest, there is a
high demand for hard
wood, which means that
the locals will get a
good price for selling it.
Tree fall gaps allow rain to reach
soil and wash away nutrients.
Roads have to be cleared for
access. Skids are created by
tractors. Log decks needed to
store felled trees so more land
must be cleared. Unmanaged, so
unsustainable. Hardwood is very
scare e.g. mahogany, so felling
these trees is wasteful
Cattle
Ranching
Little employment
because few cowboys
manage large numbers
of cattle. Many
transnational
companies own the
ranches, so profit goes
out of the country.
Deforestation because of land
clearance for ranch and roads,
fertile soils destroyed.
Mining
Mineral deposits in the
Amazon include bauxite
(the main constituent of
aluminium), iron ore,
manganese, gold, silver
and diamonds. Minerals
can be sold for high
profits. This can be
reinvested into
infrastructure. Provides
an alternative source of
employment.
Destroys forest – loss of habitat
and biodiversity. Can cause air
pollution, and water pollution in
the mining of gold etc. Power
source is often charcoal, so more
trees used to provide this. Lots of
forest cleared for roads and
railways.
Ecotourism
“Tourism based around the ecological and human resources of an area.
This includes scenic landscapes, traditional cultures and heritage. It means
small visitor numbers, sustainable use of resources, responsible travel and
conservation of the environment.”
The World Tourism
Organisation
believes that
ecotourism has a role
to play in
conservation and the
reduction of poverty
in traditional
communities in
remote regions. It is
the opposite of mass
tourism, e.g.
Package holidays.
Ecotourism groups
have a ‘Green
Globe’ to show that
they have fulfilled
all criteria.
Sustainable Tourism must:
1.
Preserve biological diversity
2.
Minimise ecological, cultural and social impact
3.
Maximise economic benefit to local communities
Alta Floresta Tourist Project,
Mato Grosso
Alta Floresta is a town in the highlands of the Amazon
rainforest, home to an innovative research centre and
ecotourism centre. It was set up to study sustainable
uses of the forest and to teach people in the area how
to use the forest responsibly. The money raised at Alta
Floresta is used for:
• Educate tourists on rainforest ecology
•Raising awareness of importance of conservation
Local people can work at the
centre so they have good
employment. The centre can be
accessed by boat only, so no
forest is cleared to make roads.
•Support the research centre in protection of natural
habitats and endangered species
•Building schools and hospitals
•Educating farmers