If you’ve been waiting all year to see beautiful fall colors in Kentucky, it is almost time. Mid-October is the beginning of the brilliant fall tree color show in Kentucky. Actually, these brilliant colors have been there all along; they’ve been masked by a cloak of chlorophylls, green pigments vital to a tree’s food-making process.

Trees use and replenish chlorophylls during the growing season. High replacement maintains green leaf color. As fall approaches, the green pigments are replaced at a slower rate due to complex environmental factors and the trees’ genetic makeup. The dwindling supply of green pigments unmasks other pigments that were present all along, revealing the spectacular show of fall color.

We can enjoy a variety of fall colors because our diverse climate and soil composition enable many trees from northern and southern states to grow in Kentucky.

Various shades of red color are produced by black gum, pear, sumac, dogwood, maple, oak and sassafras trees. Those giving us a range of orange and yellow hues include yellow-poplar, birch, hickory and beech.

Since black gum and sumac trees shut down chlorophyll production early, they are the first to reveal fall color. Both change from green to red, leaf by leaf. No leaf seems to be all green or red at the same time, giving a spotty appearance throughout the trees.

You might be surprised to know that what actually makes leaves change color has less do with “Jack Frost” and more to do with shorter days activating a kind of “chemical clock” telling the trees to shut down chlorophyll production and prepare for winter.

When the tree completely shuts down chlorophyll production, a layer at the base of the leaf forms. This abscission layer causes the leaf to fall off the branch, leaving only the bud with next year’s leaves and flowers to wait for the signal in the spring to bloom and grow.

For more information on fall tree color or other forestry topics, contact your Bell County Cooperative Extension Service Office.

Stacy White is the Bell County extension agent for agriculture and natural resources. Educational programs of the University of Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability or national origin. Source: Billy Thomas, UK extension forester