Every year, mother nature puts on a spectacular show across the Northeast, Southeast and Midwest United States. Autumn colors can be seen in many areas throughout the U.S., and the world for that matter. However, it is certain areas of the United States, including the Northeast corridor, Southeast U.S. along the Appalachian Mountain chain, and much of the Midwest that produces the most striking and vibrant colors. This is attributed to mild autumn days coupled with cool, crisp, but not freezing evenings. During September, October and November, the once green leaves of spring and summer alter their appearance, displaying such colors as brilliant yellow, glowing orange, fiery red, and rich brown. Each species of tree and shrub has its own unique hues which can vary from year to year. So why do the leaves go through this transformation? This tutorial will help you understand the foliage process.
Science is used to explain many phenomena and foliage is no exception. The two major branches of science which impact the foliage are meteorology, or the weather, and biology. The following sections will describe the impact both have on the fall foliage.