Where is Amazon

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Where is Amazon ?
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Where is Amazon ?

• one of the world's great rainforests
• Amazon river runs 3,000 miles from the Andes to
  the sea
• The vast Amazon basin covers more than two and a
  half million square miles

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Climate

• High and constant temperature27c
• Small annual and diurnal temperature range
• Very little seasonal difference
• Heavy annual rainfall2ooomm
• Reliable and evenly distributed
• High humidityover 80

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Deforestation

• ????

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Characteristics

• It involves the permanent destruction of
  indigenous ??? forests and woodland for farming
  or commercialpurpose.
• For subsistence purpose, trees are cut down by
  primitive tools burnt. The remaining ash is
  used as fertilizer for farming.

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For commercial purpose

• Trees are cleared extensively with the help of
  modern technology ( e.g. Electric saw, road ) to
  make furniture and paper.
• Trees are removed for rearing , mining .This
  will give greater impact on the environment
  because there is no plant to protect the soil .
  The land was abandoned after used.

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Data about deforestation

• In Amazon

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Deforestation of Brazil
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Dead forest
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Deforestation
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Original forest
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Deforestation in Amazon
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Shifting Cultivation

• ????

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Characteristics

• It is a type of subsistence ???? farming due
  to crops are grown for household use only
• It is practiced by native tribes ?? in hilly
  areas
• Climate is equatorial climate with high
  temperature and abundant rainfall
• Population density is low
• Farms are scatterly distributed , separated by
  forests or savanna
• Fields are small

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• Clearing of trees provides farmland
• The method of slash and burn ???? is
  adopted to clear and fertilize the farmland
• Some simple and primitive ??? tools , like
  wooden plough , are used to cultivate the
  farmlands and labour input is low
• The crop yield is low
• Farmland is temporary ??? as soil becomes
  infertile after heavy leaching , and two to three
  years of cultivation
• Bush fallowing will be practiced as the soil
  becomes infertile

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• The application of chemical fertilizers and the
  construction of irrigation network are
  unnecessary
• Shifting cultivators abandon ?? the old
  farmland and move to a new site to start
  cultivation again
• As harvest ??? is low and unreliable ,
  shifting cultivators also practice hunting ??
  , fishing , fruit-gathering ???? and livestock
  rearing to increase food supply

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Shifting cultivation
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Map
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Rainfall in Amazon
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Data about shifting cultivation
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• With the help of stone axes ? and machetes ,
  the Amerindians clear a small area of about 1
  hectare ?? in the forest .
• Sometimes the largest trees are left standing to
  protect young crops from the suns heat and the
  heavy rain There are also trees which provide
  food , such as the banana and kola nut ???
  left behind or planted purposefully to protect
  crops. The buttress roots of the giant ???
  trees are left also.
• The main crop , manioc ?? , is planted along
  with yams ( which need a richer soil ) , pumpkins
  , beans , tobacco ?? and coca ?? .
• The Amerindian diet is supplemented by hunting ,
  mainly for tapirs and moneys , fishing and
  collecting fruit .

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Impact of deforestation and shifting cultivation
in Amazon
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Why changed?

• Where the population density is low enough to
  permit sufficiently long period of fallow, the
  soil fertility may be maintained by means of
  grassland (in the savanna regions), and by
  secondary growth of forest (in forest areas),
  then this method of farming may be considered
  suitable to primitive tribes with a low level of
  technology 
• Recent government policy of encouraging the
  in-migration of landless farmers from other parts
  of the country , together with the development of
  extensive commercial cattle ranching , has meant
  that sedentary ?? farming is rapidly replacing
  shifting cultivation . After just a few years, as
  should have been foreseen, large tracts of some
  cattle ranches and many individual farms have
  already been abandoned as their soils have become
  infertile and eroded
•  

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Atmosphere

• The local energy budget is changes
• reduces the surface vegetation cover and raises
  the surface radiation from about 13 - 20more
  solar radiation is reflected , the less the
  surface will be warmed
• however, this cooling effect is rejected by a
  great reduction of evapo-transpiration that
  transformed into heat and making the surface
  hotter

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Atmosphere-global impact

• Burning, urban development (e.g. industry and
  mining) may increase the production of carbon
  dioxide.
• Carbon dioxide cannot go out to the space as
  there is less vegetation to absorb carbon
  dioxide.
• This leads to increase the air temperature and
  the planet becomes warmer and warmer. (Greenhouse
  effects)
• Global warming may lead to the melting of polar
  ice and rising the sea level

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Lithosphere

• Biochemical cycle will break up
• It is because the less the vegetation, the less
  the litter. The fungi still decompose very fast
  while there are only a little amount of litter.
• An insignificant part of soil is actually washed
  away by rain, the quick recycling mechanism is
  broken

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Lithosphere - local effect

• Large areas are wasted.
• This leaves the land exposed to heavy rain and
  leaching resulted.
• The productivity of the rainforest depends upon
  the rapid and unbroken recycling of nutrient.
  Once the forest has been cleared, the nutrient
  cycle is broken.
• Widespread soil exhaustion makes it difficult and
  slow to recover the land.
• Soil erosion often results after the removal of
  vegetation cover.
• Heavy, afternoon, convectional rainstorms hit the
  unprotected earth. The humus in the upper layers
  of the soil is rapidly destroyed or washed down
  (causing erosion and leaching)

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Lithosphere-local effect

• With the source of humus removed (litter), and in
  the absence ?? of fertilizer and animal manure
  ?? , the ferralitic soil rapidly lose their
  fertility and the soil is rapidly leached by the
  frequent and heavy tropical rain.
• Raindrop ?? impact and rain washes erode the soil
  and carry it into streams, lakes and reservoirs
  that cause silting and flooding in the lowlands.
•  Within 4 or 5 years , the decline in crop yields
  and the re-infestation ?? of the area by weeds
  force the tribe ?? to shift to another part of
  the forest . Although shifting cultivation
  appears to be a wasteful use of land , it has no
  long-term adverse ??? effect upon the
  environment as , in most places , humus can built
  up sufficiently to allow the land to be re-used
  within 25 years if necessary

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Hydrosphere

• It also changes local water cycle
• Before deforestation, there are
  evapo-transpiration and so that there are only
  30 runoff.
• After deforestation, there are 90 runoff because
  no evapo-transpiration ...gt leading to flood
  easily
• It increases the rate of the process of
  laterization, which causes poor drainage.
  Moreover, it reduces infiltration and hence soil
  moisture content also reduces.

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Hydrosphere -Influences on the area adjacent to
the forest

• Increases overland flow in the water records of
  River Maranon a tributary of the Amazon so
  that cause flood hazards

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Biosphere

• People who live there will extinct because of
  losing their home in rainforest. They will die
  easily as they are not suitable for the outside
  environment.
• An increase in population often makes it
  necessary to shorten the period of fallow . This
  means insufficient time for the soil to recover
  and for the forest to regenerate

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Biosphere

• Those wildlife habitats and species which may be
  useful for human beings are threaten and extinct.
  
• The insects become extinct ??? before they have
  been discovered.
• For example, the Brazil nut flowers will not
  produce the nuts without large carpenter bees to
  visit their flowers.
• The rainforest is also a home to numerous ???
  migratory birds ??.

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Biosphere

• Of the estimated 6 million Amerindians living in
  the Amazon rainforest when the European colonists
  arrived , only about 4 per cent remain today as a
  result of illnesses caught from and death
  inflicted by the invaders
• Burning destroyed weeds and controls the growth
  of weed seeds for some time

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Biosphere

• Adverse change in composition and structure of
  vegetation for example, the height, species, and
  density decrease. The structure of vegetation
  becomes from complicated to simple
• Climatic climax community may be totally
  destroyed and turned into bare earth. The loss of
  vegetation leads to loss of animal life or
  extinction of some animal species.

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The End

• By Lois Li Man Wai
• Chan Yuen Hung
• Lo Wing Suet