Nutrient Loss Accelerated
by Clear-Cutting of a Forest
Ecosystem
Reviewed by Michele Dixon and
Ryan Lenet
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
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.
Small WaterShed Concept
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.
Eutrophication Process
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.
Nitrogen Cycle
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.
Clear Cut Forest Picture
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)
Data
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.
Conclusion 2
Management of forest ecosystems
can significantly contribute to
eutrophication of ecosystem water.
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.
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