Nutrient Loss Accelerated by Clear-Cutting of a Forest Ecosystem

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Nutrient Loss Accelerated by Clear-Cutting of a
Forest Ecosystem

• Reviewed by Michele Dixon and Ryan Lenet

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Purpose

• This was an experiment that was designed to
• 1. Determine the effect of clear
• cutting on stramflow
• 2. Examine some of the
• chemical relations of the
• forest ecosystem
• 3. Evaluate the effects of forest
• manipulation on nutrient relations
  
• and on eutrophication of stream
• water

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Background

• The importance of the article is that it was the
  first controlled experiment in a forest ecosystem
  using small watersheds in the Central New
  Hampshire Forest.

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Small WaterShed Concept
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Some Important Terms

• 1. Eutrophication is the increase in additions of
  nutrients (especially nitrogen and phosphorus) to
  fresh water systems, which lead to increase in
  plant growth and often to undesirable changes in
  ecosystem structure and function.

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Eutrophication Process
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One more Important Term

• Nitrification is the biological oxidation of
  ammonia with oxygen into nitrite followed by the
  oxidation of these nitrites into nitrates.
  Nitrification is an important step in the
  nitrogen cycle in soil.

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Nitrogen Cycle
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Procedure

• Samples of stream water were collected and
  analyzed weekly for two years prior to the
  experiement.
• Then in the winter of 1965-1966, the forest was
  leveled. No products removed and care was taken
  to minimize erosion of surface.
• Samples of stream water were collected and
  analyzed weekly.
• Similar measurements were taken by nearby
  watersheds.

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Clear Cut Forest Picture
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Added Variables

• The Herbicidal Bromacil was added to the
  clear-cut forest to inhibit growth.
• ( According to the article Bromacil had little
  effect on nutrient loss - about a 5 effect)

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Data
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Conclusion 1

• Clear cutting tends to deplete the nutrients of a
  forest ecosystem by reducing transpiration and so
  increasing the amount of water passing through
  the system.

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Conclusion 2

• Management of forest ecosystems can significantly
  contribute to eutrophication of ecosystem water.

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Conclusion 3

• Clear cutting of a forest ecosystem accelerated
  nutrient loss
• Example- increase loss of
• cations correlate with the
• loss of nitrate which inhibits
• the process of nitrification.

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How to Integrate this model
in your Classroom

• http//tiee.ecoed.net/index.html
• References
• 1.www.wikopedia.com
• 2.www.agiweb.org/geotimes/aug03/
• feature_hubbard.html