Correlation Between Autumnal Leaf Senescence and Age in Acer platanoides Norway Maple Yana Radenska

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Correlation Between Autumnal Leaf Senescence and
Age in Acer platanoides (Norway Maple)Yana
RadenskaEDTEP 586
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• Question
• Is there any correlation between age and the
  timing of autumnal leaf senescence in the Norway
  maple tree?
• In other words, if I went out on a single Fall
  day, looked at a bunch of trees of the same
  species (Norway maples, in this case), would I
  see any difference between smaller and larger
  trees in terms of what percentage of the leaves
  had turned colors other than green?

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Initial Model
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Assumptions

• Environmental factors are the same
• Temperature
• Day length
• Amount of sunlight
• Variation in leaf loss within species is
  negligible
• Diameter at Breast Height is a good indicator of
  age

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Methods

• Observations performed on 10/29/05
• Observed 33 Maple trees, E8 and road on campus
• Data taken
• of leaf senescence (as determined by two
  people)
• Location (using GPS)
• Orientation (using a compass)
• Circumference (to determine Diameter at Breast
  Height)
• Other factors (such as substantial shade)

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Data Collection
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Results
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Culminating Argument

• Causal mechanisms
• DNA in all organisms degrades during the process
  of replication as the organism ages
• Older organisms have more dysfunctional DNA
  (through replication errors and shorter
  telomeres)
• DNA is used to produce specific proteins that are
  used to build the varying components (such as
  chlorophyll) needed to keep leaves alive and
  green, thus older trees should have non-green and
  dead leaves

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Culminating Argument Cont.

• Explanation
• Data show that there appears to be a positive
  correlation between tree age and leaf senescence
• Older trees had more brown leaves
• HOWEVER correlation ! causation
• Further study is needed to substantiate causation

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Revised Model
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Selected References

• The Chemistry of Fall Colors. October 14th, 2005.
  USDA Forest Service. http//www.fs.fed.us/r2/recre
  ation/fallcolors/chemistry/
• The Scientific Basis for Autumn. June 29th, 2003.
  NCNatural. http//ncnatural.com/wildflwr/fall/scie
  nce.html
• Andersson, A. et al. A Transcriptional Timetable
  of Autumn Senescence. Genome Biology, 2004. 5
  R24. http//genomebiology.com/2004/5/4/R24.
• Special thanks to Margaret Jones, Renata Green,
  Dawn Rubstello, Mark Windschitl, Scott Braswell,
  and Elizabeth Thomas.