Fall Leaf Assignment

Purpose of assignment:

Why does a tree loose its leaves in the northern hemisphere Fall? The purpose of this assignment is not to answer this question, but to explore the manner in which leaves are lost. What is the relationship between the rate of leaf loss and environmental factors? What is the date of first loss, last loss? Is the loss rate a continuous function or a discrete function? These are just a few of the questions you might ask yourself as you carry out this exercise.

Due Date:

Due late October/mid-November after all the leaves have fallen.

Procedure:

1. Find a deciduous tree in the vicinity of Plymouth or your place of habitation if it isn't Plymouth.
2. Determine the exact location, i.e., elevation, aspect, geographic position, single or amongst a group of trees. For purposes of this exercise, it might be easier to eliminate other variables by picking a single tree rather than a tree in a cluster.
3. Pick one branch that is at eye-level and tag it so you can return to it on a weekly basis. If you see rapid changes taking place, you may want to increase the frequency of your visits. Pick a branch that has between 15 to 25 leaves.
4. Count the number of leaves and on at least a weekly basis determine the status of each leaf. Use the following scale to grade the leaf:
   • Totally green (5)
   • Seventy-five percent (4)
   • Fifty percent (3)
   • Twenty-five percent (2)
   • No green at all (1)
   • No longer present (0)
5. Keep track of this data in a spreadsheet. I suggest the first column as a listing of leaf number (1 to 15 or 25). Subsequent columns will data associated with date of visit.
6. You will be asked to write a short report that will include some sort of graphical display of this data. I will give you specific details as to the nature of that report later on. Suffice it to say that it will be short rather than long.