DEFORESTATION by dffhrtcv3

VIEWS: 7 PAGES: 22

									DEFORESTATION
     How Forests Reduce Natural
             Hazards
• Trees prevent sediment runoff
• Forests hold and use more water than farms and
  grasslands
• Leaves capture rainwater and reduce raindrop
  impact, which decreases soil erosion
• Roots hold soil in place, reducing the movement
  of sediment, preventing landslides
• Roots create dry soil by absorbing water, which
  prevents overflow of rainwater
            What, Who, and Why?
               Deforestation
•   Clear-cuts for logging and pulp wood (for paper)
•   Cultivation of land for agriculture
•   Permanent pastures
•   Open-pit mining
•   Dam Construction
•   Chemical Defoliants
•   Urban Expansion
•   Wildfires
             Harmful Behaviors,
             Harmful Side-Effects
• Paving roads and infrastructures within forests
   – Causes soil compaction
   – Blocks culverts that funnel water underground and focus
     runoff into gullies
   – Alter water runoff patterns and permanently disrupt
     subsurface water flow
   – Enables greater human access to forests, increasing the
     number and severity of forest fires
• Roads are permanent whereas clear-cuts are temporary
  and allow for regeneration
Logging roads trigger debris avalanches that accelerate
 erosion 25 to 340 times more than intact forests
   Effects of Deforestation
• Soil erosion
   – Heavy impact of rain causes increased sedimentary
     erosion and quicker runoff
   – The eroded soil is deposited into river beds, shrinking
     the channels and lowering the carrying capacity of
     water, increasing the likelihood of flooding
     exponentially
         Effects of Deforestation
• Landslides
   – Without the roots of trees to hold the soil in place,
     moderate to heavy rainwater can cause massive
     mudslides
   – Landslides, particularly mudslides, usually occur in
     steep, narrow stream channels that allow them to
     move very quickly and pick up more debris as they
     go
• Once the landslide has slowed down and
  reached a more level plane, the debris and mud
  solidify to cause blockage of valleys and streams,
  backing up water and leading to large, sudden
  floods
       Effects of Deforestation
• Floods
  – Deforestation does not directly cause floods, but it
    does exacerbate the magnitude and force of the
    floods
  – Without trees, the soil cannot absorb enough
    rainwater, causing massive runoff
                  Effects of Deforestation
Trees use CO2,
converting it into
oxygen for other
organisms to
breathe.
Deforestation leads
to higher CO2
levels, which
directly contribute
to global warming.
                         Madagascar
• Deforestation began when the island
  was annexed as a French colony in
  1896
• Due to famine and unstable politics,
  the natives fled to the forests, where
  they began using “shifting
  cultivation,” in which they cleared
  regions of the forests, sometimes by
  burning them, and used the land for
  subsistence agriculture
• Beginning in the 1950’s, the rate of
  deforestation increased dramatically
  due to population increase and
  improvements in technology
                  Consequences
• Social Consequences
  – Today, the majority of the Malagasy people live in poverty
    due to the economic exploitation of their country and are
    unable to find jobs
  – In order to create some sort of income, many natives turn to
    exploitation of their natural resources, mainly the forests. For
    them, it is a choice between their own lives and livelihood of
    the forest
  – Large corporations have a great deal of influence on whether
    or not deforestation continues because the Malagasy
    government needs their investments in order to survive.
               Consequences
• Environmental Consequences
  – By 1985, only 34% of the original forest in
    Madagascar remained
  – Lack of trees leads to increased likelihood of violent
    floods and mudslides
  – Soil erosion causes the runoff of sediments, leaving
    the deforested area barren. The runoff prevents not
    only the regeneration of the forest but also inhibits
    further growth from relief efforts.
Due to the color of the sediment runoff in Madagascar, many have
commented on aerial photography, like this one, by saying that it appears as
though the country itself is bleeding. In a way, that is exactly what is
happening.
Yellow River Floods: Yangtze, China
           Is Deforestation to Blame?
• Controversy over whether two decades of
  deforestation contributed to serious floods in
  1998 (4,000+ casualties)
• “logging carried out without a policy of
  sustainable forest management”
• Lost 30% of forest cover in the last 15 years,
  85% altogether
                1998 Floods
• Soil erosion on higher part of the Yellow River
  caused silting of the riverbed. This caused a
  build up of water in the central/lower part of
  the river, which eventually lead to flooding
• Deforestation robbed the land of important
  flood plain waterways
            Controversy in Beijing
• Beijing government blamed floods on small-scale loggers and
  farmers.
• Established a plan to mitigate against further floods:
   – relocated more than 1 million logging employees
   – closed hillsides to herders to allow for regrowth
   – protected 60 million hectares of forests upstream and began replanting
     programs
   – Began construction of Xiaolangdi Dam
• China linked to logging in Africa, the Amazon, Burma, Indonesia
    Haiti and Hurricane Jeanne
• Haiti has lost more than 90% of its original
  forest cover
• Jeanne left the country completely devastated by
  massive floods triggered by the hurricane
• Deforestation due to centuries of forced poverty
  by imperial domination and capitalist
  exploitation
• Jeanne had less of an impact upon Bahamas and
  Florida
        It’s Not Just The Forests…
• Environmental Refugees: people displaced due to
  environmental degradation
• Worldwide, more people are displaced each year due to
  environmental disasters than by war.
“The rapidity at which this country is being
stripped of its forests must alarm everything
    thinking man…It is high time that we
   should turn our earnest attention to this
   subject which so seriously concerns our
              national prosperity”
  -U.S. Secretary of the Interior Carl Shurz, 1877
                                 Bibliography
Butler, Rhett A. "A World Imperiled: Forces Behind Forest Loss." Mongabay.com / A Place Out of
    Time: Tropical Rainforests and the Perils They Face. 9 January 2006.

Chin, Pat. "Haiti, Hurriane Jeanne, and Class Struggle." Workers World. 7 Oct. 2004.
    <www.workers.org>.

Draffan, George, and Derrick Jensen. Strangely Like War: the Global Assault on Forests. White River
    Junction, Vt: Chelsea Green, 2003.

Jarosz, Lucy. "Defining and explaining tropical deforestation: shifting cultivation and population
    growth in colonial Madagascar." Economic Geography 64.9 (Oct 1993): 366-80.

Miles, James. "China Tries to Combat Floods." BBC News. 13 July 1999.
    <http://news.bbc.co.uk/2/hi/asia-pacific/393822.stm>.

"Deforestation Case Study: Madagascar". http://www.sprl.umich.edu/GCL/forestlab.html

"Flood of Evidence." The Why Files. <http://whyfiles.org/107flood/3.html >.

"Is China Ready for More Floods?" BBC News. 12 June 2002. < http://news.bbc.co.uk/2/hi/asia-
     pacific/2040548.stm>.

“Landslides” http://www.ussartf.org/landslides.htm (United States Search and Rescue Task Force)

								
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