Article courtesy of Jeanie Martin
In the next few weeks the trees in the Southern Appalachians will get all gussied up in their fall finery. Ever wonder why some year’s fall color is more spectacular than others? The answer starts with knowing what’s going on in the trees’ leaves.
During the spring and summer the trees make chlorophyll in the leaves, a chemical that allows them to “eat” sunlight and turn it into food. Chlorophyll reflects the color green and our eyes see the reflected color. There are other pigments in the leaves that are masked by the green. Chlorophyll breaks down easily in cold and in sunlight, so the tree makes other pigments to protect the chlorophyll from light and to capture the energy the chlorophyll misses.
These other plant chemicals are powerful antioxidants, the same ones that we are encouraged to get in our food to keep us healthy. One group is anthocyanins and they reflect red or purple. Another group is the carotenoids, which reflect yellow and orange.
As the length of day shortens in the fall, the trees decrease the production of chlorophyll, the green fades and the other color pigments begin to show through. A cold snap will enhance the fall colors as cold breaks down the chlorophyll even quicker.
Conditions for the best fall color would include a warm, wet summer so the trees would have made lots of leaves and pigments. Then a fall that is dry, sunny and cool at night intensifies the color. A cold snap starts the show. Because we have lots of microclimates in our region, different areas get different weather causing pockets of varied color patterns. Soil pH also plays a part in the red leaves. The more acid the soil, the more bright red we see such as with red maples. The less acid, the leaves turn more purple, like in the sourwoods. With over 100 species of trees in the Southern Appalachians, the diversity alone ensures us that at least some of the tree species will be having a good year. Enjoy the show this fall Haw Creek!