Correlation Between Autumnal Leaf Senescence and Age in Acer platanoides (Norway Maple) Yana Radenska EDTEP 586
Correlation Between Autumnal Leaf Senescence and Age in Acer
platanoides (Norway Maple)
Yana RadenskaEDTEP 586
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?
Initial Model
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
Methods
Observations performed on 10/29/05Observed 33 Maple trees, E8 and road on campusData 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)
Data Collection
ResultsDBH v. % Leaf Senescence
y = 6.4877x - 9.7962
R2 = 0.613
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16
Diameter at Breast Height in Inches
% L
eaf
Sen
esce
nce
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
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
Revised Model
Selected ReferencesThe Chemistry of Fall Colors. October 14th, 2005. USDA Forest Service.
http://www.fs.fed.us/r2/recreation/fallcolors/chemistry/The Scientific Basis for Autumn. June 29th, 2003. NCNatural. http://
ncnatural.com/wildflwr/fall/science.htmlAndersson, 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.