Certain areas in the United States have very dramatic leaf color changes.  However, the changing of leaf color is a widespread phenomena that is enjoyed by many people.   These activities are for a "typical" tree and are not for a particular location, but are generalized across the United States.  You can adapt these lessons for your particular area by changing the latitude.

Daylight  Model using Mathematica® modeling software to see how photoperiod is a function of latitude and day of year.  You will need to download this file: Lat.txt to run the notebook.  If you do not have Mathematica®, you will need to download and install the free Math Reader® from http://www.wolfram.com/products/mathreader/ to see the model.

Leaf Color Model using Mathematica® modeling software to see how latitude location affects the photoperiod which controls the leaf color change. You will need to download this file: Lat.txt to run the notebook.  If you do not have Mathematica®, you will need to download and install the free Math Reader® from http://www.wolfram.com/products/mathreader/ to see the model.

Graph Showing the Effect of Photoperiod on Plant Physiology.  An Excel® graph that shows how the length of photoperiod changes a plant's physiology.

Graph Showing the Effect ofPhotoperiod on Plant Pigments.  An Excel® graph that shows how the length of photoperiod affects a plant's pigment production.

Notes on abscission zone production Notes to the teacher explaining the role plant hormones play in the formation of the abscission zone in a leaf and the resulting effects on plant pigments.