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DEFORESTATION
DEFORESTATION
• Deforestation is
the logging or
burning of trees
in a forested
area
There are several reasons
deforestation occurs:
•
•
•
•
Commodity
Pasture
Plantations of commodities
Human settlement
DEFORESTATION
• The removal of trees without sufficient
reforestation has resulted in:
- damage to habitat
- biodiversity loss
- aridity
DEFORESTATION
• Deforested regions
often degrade into
wasteland
DEFORESTATION
Why deforestation occurs?
• Disregard or ignorance of intrinsic value
• Lack of recognized value
• Lax forest management
• Deficient environmental law
- Some of the factors that allow
deforestation to occur on a large scale.
Why trees matter?
• Forests must first be
given credit for what
they bring to global
ecosystems
• The quality of life that
all species maintain
gives ecological
balance
Why trees matter?
• Tropical Rainforests presently give a place
to call home for 50% - 90% of all
organisms
• 50 million creatures that can live no place
but the rich rainforests
Why trees matter?
• Not only are other
species at risk
• The human race
also benefits from
what the trees give
Why trees matter?
• According to the World Rainforest
Movement:
- 25% of medicines come from the
forests
- this is a number that does not do
justice to all the cures that have yet to be
discovered or that have been destroyed
Why trees matter?
• The forests give life, not only to other
species, but they help to prolong the
human race
• Trees improve the quality of the air
- by trapping carbon and other particles
produced by pollution (CARBON SINKS)
Why trees matter?
• Preventing erosion
and landslides
• Mother earth has
given much
responsibility to
trees
Causes of Deforestation
• inequitable distribution of wealth and
power
• population growth
• overpopulation
• urbanization
• globalization
• corruption of government institutions
Deforestation is due to:
• 5% cattle ranching
• 19% over-heavy
logging
• 22% growing sector
of plantations
• 54% due to slashand-burn farming
Environmental Problems Caused
by Deforestation
Atmospheric
• Deforestation is ongoing and is shaping:
- climate
▪ major causes of the enhanced
greenhouse effect
- geography
Atmospheric
• Rainforests are widely believed to
contribute a significant amount of world's
oxygen
• Forests are also able to extract carbon
dioxide and pollutants from the air, thus
contributing to biosphere stability.
Hydrological
• Deforestation
affects water cycle.
• Trees extract
groundwater
through their roots
and release it into
the atmosphere
(TRANSPIRATION)
Hydrological
• When part of a forest is removed, the trees
no longer evaporate away this water,
resulting in a much drier climate.
• Deforestation reduces soil cohesion, so
that erosion, flooding and landslides
ensue.
Soil
• Deforestation generally
increases rates of soil
erosion.
• Tree roots bind soil
together.
• Undisturbed forest has
very low rates of soil loss.
Ecological
• Deforestation results
in declines in
biodiversity
• Forests support:
- biodiversity
- providing habitat for
wildlife
- forests foster
medicinal
conservation
Economic Impact
• Damage to forests affect
living standards for the
world's poor and reduce
global GDP.
Economic Impact
• Developed countries continue to utilize:
- timber for building houses
- wood pulp for paper
• Developing countries almost three billion
people rely on wood for heating and
cooking.
HISTORICAL CAUSES
• Prehistory
- Deforestation has been
practiced by humans for
tens of thousands of
years before the
beginnings of civilization
• Fire was the first tool that
allowed humans to
modify the landscape.
Pre-industrial history
• From 1100 to 1500 AD significant
deforestation took place in Western
Europe as a result of the expanding
human population
• The large-scale building of wooden sailing
ships by European (coastal) naval owners
since the 15th century for exploration.
Pre-industrial history
• Europeans had lived in the midst of vast
forests throughout the earlier medieval
centuries
• After 1250 they became so skilled at
deforestation that by 1500 AD they were
running short of wood for heating and
cooking.
Pre-industrial history
• They were faced with a
nutritional decline
• Because of the
elimination of the
generous supply of wild
game that had inhabited
the now-disappearing
forests
Pre-industrial history
• Europeans had lived in the midst of vast
forests throughout the earlier medieval
centuries
• After 1250 they became so skilled at
deforestation that by 1500 AD they were
running short of wood for heating and
cooking
Pre-industrial history
• They were faced with a nutritional decline
because of the elimination of the generous
supply of wild game that had inhabited the
now-disappearing forests,
Rates of deforestation
• Jungle burned for
agriculture in
southern Mexico
• Global
deforestation
sharply
accelerated around
1852
Rates of deforestation
• It has been estimated that about half of the
earth's mature tropical forests
- between 7.5 million and 8 million km2 of
the original 15 million to 16 million km2 that
until 1947 covered the planet have now
been cleared.
Rates of deforestation
• Some scientists have
predicted that unless
significant measures
- such as seeking
out and protecting old
growth forests that
haven't been
disturbed are taken
on a worldwide basis
Rates of deforestation
• By 2030 there will only be ten percent
remaining
• Another ten percent in a degraded
condition
• 80 percent will have been lost
• With them hundreds of thousands of
irreplaceable species.
Rates of deforestation
• In Central America, two-thirds of lowland
tropical forests have been turned into
pasture
• Since 1950 and 40% of all the rainforests
have been lost in the last 40 years
• Brazil has lost 90-95% of its Mata Atlântica
forest
•
Rates of deforestation
• Madagascar has
lost 90% of its
eastern rainforests
• As of 2007, less
than 1% of Haiti's
forests remained
Rates of deforestation
•
•
•
•
•
•
Countries who have lost large areas of
their rainforest:
Mexico
India
Philippines
Indonesia
Thailand
Côte d'Ivoire
Rates of deforestation
• Countries who have lost
large areas of their
rainforest:
• Myanmar
• Malaysia
• Bangladesh
• China
• Sri Lanka
• Laos
• Nigeria
Rates of deforestation
• Countries who have lost large areas of
their rainforest:
• Democratic Republic of the Congo
• Liberia
• Guinea
• Ghana
Rates of deforestation
• Several countries,
notably Brazil
-Have declared their
deforestation a
national emergency
Deforestation by region
• Rates of deforestation vary around the
world:
- South-east Asia
- Parts of South America
• The two regions being the highest
concern to environmentalists.
FOREST MANAGEMENT
• Efforts to stop or slow deforestation have
been attempted for many centuries
• It has long been known that deforestation
can cause environmental damage
sufficient in some cases to cause societies
to collapse
FOREST MANAGEMENT
• In Tonga, rulers
developed policies
designed to prevent
conflicts
• Between short-term gains
from converting forest to
farmland and long-term
problems forest loss
would cause
FOREST MANAGEMENT
• While during the seventeenth and
eighteenth centuries in Tokugawa, Japan,
the shoguns developed a highly
sophisticated system of long-term planning
-By substituting timber by other products
and more efficient use of land that had
been farmed for many centuries
REFORESTATION
• In many parts of
the world,
especially in East
Asian countries:
- reforestation
- afforestation
• Increasing the area
of forested lands
FOREST MANAGEMENT
• The amount of woodland has increased in
22 of the world's 50 most forested nations
• Asia as a whole gained 1 million hectares
of forest between 2000 and 2005
FOREST MANAGEMENT
• Tropical forest in El Salvador expanded
more than 20 percent between 1992 and
2001
• Based on these trends, one study projects
that global forest will increase by 10
percent
- an area the size of India by 2050.
REFORESTATION
• In China, where large scale destruction of
forests has occurred
-The government has in the past required
that every able-bodied citizen between the
ages of 11 and 60 plant three to five trees
per year or do the equivalent amount of
work in other forest services.
REFORESTATION
• The government claims that at least 1
billion trees have been planted in China
every year since 1982
• This is no longer required today, but March
12 of every year in China is the Planting
Holiday.
REFORESTATION
• Different conservation
group were established
FOREST PLANTATION
• One analysis of Food and Agriculture
Organization data suggests that :
- afforestation
- reforestation
• “Could reverse the global decline in
woodlands within 30 years."
Deforestation in the Philippines
• Spanning the past 5 decades, 2/3 of the
forests of the Philippines have been
deforested
• Causing it to attain one of the highest
deforestation rates in the world
Deforestation in the Philippines
• Now the
Philippines is
facing:
- floods
- poor water quality
- infertility of soil
Deforestation in the Philippines
• Have lessened development opportunities
and a majority of the population
impoverished
• The Philippines must take appropriate
action
Deforestation in the Philippines
• The Philippines
was Asia 's most
bountiful provider
of rainforest timber
during the 20th
century
Deforestation in the Philippines
• Deforestation became an obvious issue in
the 1970's
But bans on logging were never
introduced
• Loggers were barely supervised
• Little attention was paid to working on the
reducing raw log exports
Deforestation in the Philippines
• In 1986, such a ban was implemented
• But continuing efforts were short of
success
• Insufficient resources make ceasing illegal
logging practices very difficult.
Deforestation in the Philippines
• The Philippines ,
because of
deforestation have
become one of the
hardest hit
countries by
natural disasters.
Deforestation in the Philippines
• Until the government of
the Philippines can look
towards the future
• Instead of immediate
economic gain potential
• Deforestation will
continue.
CAUSES OF DEFORESTATION
• L.O: To know about the causes of
deforestation including:
– Timber extraction
– Agriculture
– Mining
– Transport
– Settlement
Development in the Amazon
Large Scale Development in the Amazon
Serious, large scale deforestation started in the Amazon
in the 1970s when the Brazilian government started to
open up the Amazon for development. This included
encouraging and funding the following projects:
Logging / timber extraction
Ranching and agriculture
Mining
Road and rail development /
transport improvements
Settlement
Hydroelectric Power (HEP)
Logging
Commercial logging / timber extraction is one of the
largest causes of deforestation. Logging companies sell
timber, mainly for use in construction industries.
Slash and burn is used to clear the land for
settlement and ranching.
Cattle Ranching
Large areas of the Amazon
have turned into cattle
ranches.
Agriculture and Settlement
Growing Crops and Settlement
More and more land is cleared to plant
crops to feed Brazils increasing
population.
In addition, the government relocated
large numbers of people to farms in the
Amazon rainforest, in an attempt to
provide opportunities for land-less
farmers and to reduce the pressure on
over-crowded urban areas in the southeast of Brazil.
Plantation Farming
Cash crop production (e.g. rubber, sugar,
coffee) by large companies can account
for large areas of the forest being
cleared.
Developments in the Amazon
Carajas Project
Belem
Sao Luis
Tucurui
iron ore,
copper,
manganese,
nickel,
bauxite, gold,
tin, lead, zinc
rail link
Carajas
0 100km
TransAmazonian
Highway
Mining
Large quantities of valuable natural resources have
been discovered in the Amazon Rainforest. They
include iron ore, bauxite, gold and other minerals.
Mining
There are two types of miners in the Amazon –
1) miners that work in the official mines which are regulated by the
Brazilian government
2) illegal miners such as the gold prospectors (garimpeiros).
•Both sets of miners have caused damage to the ecosystem by cutting
down large areas of forest and by using chemicals to purify their metals.
•However, the official mines have made some efforts to repair some of the
environmental damage they have caused. For example, at a large
bauxite mine on the Trombetas River in the state of Para, the mining
company has stopped dumping their tailings (sludge from washing the
ore) into the river and they have started a reforestation project.
•The garimpeiros are more difficult to monitor. They use enormous
amounts of mercury to purify the gold and this toxic metal is released into
the rivers and is absorbed into the food chain.
Road Building
Many roads have been built
through the Amazon to
develop the region and
move timber, cattle,
minerals and crops.
What impact does road building have on the
Amazon’s ecosystem?
Organise these statements into the flow chart below.
There is more than one correct order.
it is difficult to
grow crops
the area become
more accessible
there is no vegetation
to intercept the rain
other large scale
developments
such as mining
come to the area
trees are cut down
more trees
are cut down
road is built
the nutrient cycle is
broken and so the
soil becomes infertile
people migrate to the
area
the soil is washed away
Tucurui Dam
Tucurui Dam was built between 1976 and 1984, on the
Lower Tocantins River in the state of Para, approximately
300km south of Belem. The reservoir created upstream of
the dam is over 2000km2. The dam will produce more than
4000 MW of electricity.
Tucurui Dam – cost $5 billion
Describe the dam’s impact on the landscape.
Road
River Tocantins
Tucurui
Dam
HEP
plant
flooded an area
5 times the size
of the
Isle of Wight
Amazonian
Indian villages
Before Tucurui Dam
After Tucurui Dam
Match the statement with the correct person
Who gained and who lost out from the Tucurui Dam’s construction?
The cost of building dams…
Then the water in the lake and what the lake releases,
Is crawling with infected snails and water born diseases.
There’s a hideous locust breeding ground when the water
level’s low…
by K E Boulding
Why was road building such as the TransAmazonian
Highway vital to all these large scale development
projects?
Deforestation
Less
vegetation
Soil becomes
infertile
Fewer leaves fall
Broken
Nutrient cycle
Less nutrients
enter the soil
Less decomposition
(breaking down) of litter by
termites, fungi and bacteria
Desertification….What is It?
• Land degradation in
arid, semi arid and dry
sub-humid areas due to:
– Over cultivation
– Overgrazing
– Deforestation
– Poor irrigation
practices
Problems with Desertification
• Drought - Irregular precipitation
• Populations in these areas used the methods of shifting
agriculture and nomadic herding to respond to these
challenges but…
changing economic and political circumstances,
population growth, and a trend towards more settled
communities has increased desertification
• The Earth's drylands are found in more
than 110 nations, and moderate to severe
land degradation has reduced the
productivity of more than 70% of these
areas..
Levels of degradation in the
world
Consequences…
• reduces the land’s resilience to
natural climate variability.
• Soil becomes less productive
• Vegetation becomes damaged or
lost
• Some of the consequences are
borne by people living outside
the immediately affected area
• Food production is undermined
• Desertification contributes to
famine
• Desertification is a huge drain on
economic resources
Africa and Desertification
• 2/3 of the continent is desert or drylands.
– affected by frequent and severe droughts.
• Many African nations are landlocked, have
widespread poverty, need external assistance
and depend heavily on natural resources for
subsistence
– few institutional, legal, scientific, technical and
educational resources
• linked to migration and food security-Sahel
zone (southern border of the Sahara Desert )
What about North America?
90% of arid land impacted
• overstocking (livestock)- contributes to
erosion and desertification.
• excessive withdrawals of groundwater resulting in a rapid decline in height of the
water table.
• salinization – from salts left behind on the soil
surface after the irrigation water has
evaporated.
Process via which land turns into
desert.
Label the Sahel on
your map.
•Semi-arid area.
•Periods of rainfall and drought.
•Supports small bushes and trees.
•1950/60’s, there was above average rainfall,
causing nomadic herders to settle and farmers to
intensify agriculture.
•1970’s, there was below average rainfall leading to
extreme drought.
•Overgazing. Traditional nomadic tribes settle in one
place. Vegetation no longer protected the soil.
•Cutting down trees. Trees provided protection for the
soil, from wind and rain.
•Intensive agriculture. The growing of cash crops,
depleted the soil fertility of the area. The soil structure
breaks down.
Put the following statements into the correct
order as a flow diagram.
Vegetation roots
bind the soil.
Wind will blow
away the soil.
Leaves are no
longer present to
intercept rain. The
soil is washed
away.
Vegetation dies.
Soil is left
exposed.
Sun bakes the soil
and it cracks.
The soil is
degraded, over
time losing
fertility and
structure.
•Soil erosion.
•Sun baked, cracked soil.
•Loss of plants and animals. (Reduced Biodiversity).
•Gullying.
•Dry rivers.
•Growth of desert.
•Increase in sand storms.
•Flash floods
•Crops and cattle die, resulting in famine.
•Death.
•Migrants move to cities, resulting in the growth of
informal settlements, shanties, in already
overpopulated urban areas.
Plant Trees.
•Roots bind the soil together. Leaves provided shade,
and intercept water.
•Cheap, long term.
•Provide fuel wood and building materials.
Terracing.
•Prevent rainfall from washing away topsoil and
nutrients.
•Cheap to build, only man power needed.
Magic Stones.
•Similar to terracing, stones are placed along
contours.
•Topsoil can not be washed past the stones. Water
infiltrates, instead of running over the surface.
•Cheap to build, only man power needed.
•Effective, shown to increase yields by 50%.
Aidan.