According to the 2009 Farmers’ Almanac, most of the U.S. is just days away from the best leaf peeping of the season! For example, in Northern Illinois, where Home School, Inc. is located, the Almanac predicts that the best days for us to take a walk in the forest will be October 12-22. As the leaves change from green to brilliant hues of red, yellow and orange, one can’t help but wonder about the process.
We all know that deciduous trees need water, carbon dioxide and sunlight to produce food (glucose) through photosynthesis. Chlorophyll absorbs the light in photosynthesis and is also the chemical pigment that makes leaves appear green. In fall, when sunlight and water are scarce, photosynthesis stops. Eventually, the chlorophyll disappears, allowing other pigments in the leaf to come to the surface. Did you know that red leaves, like those from maple trees, are red because of trapped glucose? Some leaves are brown due to a build up of tannins, or waste products.
So, why do leaves fall? At the base of each leaf’s stem is an ‘abscission’ layer of cells. Abscission means to cut away. In fall, this abscission layer swells and the veins that carried food and moisture to the leaf all summer long are ultimately closed off, causing the leaf to separate from its branch and fall to the ground. Trees shed their leaves to conserve energy through the winter months and in doing so, provide a spectacular display of color for our enjoyment and appreciation.
Article by: Home School, Inc. Des Plaines, IL 60018 (800)760-7015
Leave a Reply