| In just one year's time, a tree's leaves go through an entire life cycle. First come the blossoms. Then come the small buds that burst forth into crisp, green leaves. After a few months, the leaves start to change to a color in the gold-red-brown spectrum and then, quietly and ever so gently, they fall off of the tree to lie on the forest floor. It is a pretty miraculous cycle when you stop to think about it, but what makes it happen? Basically, there are three things that contribute to the change in a leaf: the color-leaf pigments, length of night, and weatherÉalthough probably not in the way that you would think. You see, there are always three pigments in every leaf - chlorophyll (green), carotenoids (yellow, orange, and brown), and anthocyanins (red, purple) - and the amount of light available to the leaf will determine which of those three takes precedence and thus will determine the color of the leaf. As the days get shorter and less light is available for photosynthesis, the chlorophyll loses dominance until it is eventually destroyed. It is at that point that the other two pigments are unmasked and create the spectacular rainbow that makes Autumn such a magical time. |