The foliage of trees and shrubs begin to change color during the fall from their from mostly green to a range of colors from oranges and reds to gold.

Where do these colors come from? Why do some plants turn bright yellow and orange, while others warm to purple or red?

The difference in the plants is very much like that of individual people. It is determined by hereditary factors to a large degree.

As fall approaches, the plants begin to receive signals, which help them prepare for winter. The slightly lower temperatures along with the shortening length of the day tell plants to slow down their growth.

During spring and summer, green is the most common leaf color. This is due to the tiny structures in the leaves that contain green coloring, called chlorophyll. Throughout the growing season, these bodies die and are replaced on a regular basis. This orderly process continues to take place until winter approaches. At that time in time, each leaf produces a corky layer at the bottom of the leaf stalk. This layer stops movement of minerals, water, and nutrients required by the chlorophyll bodies from reaching the leaves. As a result, the chlorophyll bodies begin to die and aren’t replaced because of the lower temperatures.

In those trees that turn yellow, such as walnuts, yellow poplar, and sycamore, the yellow color has been present all the time. However, we couldn’t see it because it was concealed by the chlorophyll. Only now as the chlorophyll disappears is the yellow actually visible.

Those plants whose leaves turn red arrive at their fall color by a different route. Examples of red ones include oaks and maples. The corky layer at the bottom of the leaf stalk develops. In turn, this keeps the plant sugars from moving out as they normally do from the leaves to the roots as they do throughout the growing season. The plant then converts this sugar to red and purple pigments.

The color change is a gradual process that occurs over a period of time within a geographic area. Most of the time a specific species will begin to change color regardless of its elevation. In other words, differences in elevation don’t really result in dogwoods changing color at different times in different locations.

Fall color change doesn’t happen according to the calendar. It will happen sometime during the fall months, but we can’t know in advance what the dates will be. This past year, the color change in western North Carolina was very late, probably due to the unusually warm fall temperatures and the dry growing season.

“The Colors of Fall-A Celebration of New England’s Foliage Season” by renowned photographers Jerry and Marcy Monkman was released by The Countryman Press. For fans of fall color, the most favored destination by far is New England. This book provides a photographic essay of the very best the area has to offer. In this volume, the authors take readers off the beaten path. The result is an intimate look presented through breathtaking photos. Many of these are two-page spreads. There are both close-ups and panoramic views.

In addition, the authors delve into the science behind color change, explaining how and what this process involves. This book also includes color maps showing the best sites for seeing color in the area.
The authors’ work has been showcased in leading magazines.