Trees in southcentral Kentucky are just beginning to show fall color.
According to the Kentucky Department of Tourism, officials with Barren River Lake State Resort Park and Mammoth Cave National Park are reporting a 20 to 25 percent change in leaf color this week.
Sunlight, temperature and moisture all influence fall leaf color.
“Leaf color comes from a coloring substance known as pigment. Green leaves contain the green pigment called chlorophyl. Inside the cells of leaves, chlorophyll absorbs sunlight, but it doesn’t use the sunlight’s entire rainbow of colors,” said said Lynn True, information officer for the Kentucky Division of Forestry in Frankfort. “It absorbs only the red and blue part of the spectrum, so the light that reflects back to our eyes is green.”
As the days become shorter in the fall and there is less sunlight available, the leaves produce less chlorophyll and a yellow pigment called carotenoid begins to show through, she said.
“Carotenoid creates the bright yellows and oranges. A red pigment, called anthocyanin, is also produced as a result of cooler temperatures. Anthocyanin gives leaves the different shades of red and purple. The browns come from tannin, a by-product of photosynthesis which is left in the leaves,” True said.
How colorful autumn will be in southcentral Kentucky depends on the weather.
“If we get a nice cold front we might get a nice colorful fall,” said Larry Johnson, a park ranger at Mammoth Cave National Park, adding that a long summer promotes a brown fall, meaning leaves will likely turn brown and fall off early.
How wet or dry an area has been also plays a role in how colorful autumn will be.
“We’ve kind of been in a drought and because of that some of the trees will be losing their leaves earlier they usually do,” said Kristin Goodin, Barren County extension agent for horticulture.
Kentucky features a variety of trees that can produce brilliant fall colors.
“Our state has one of the most diverse forest ecosystems in the world with over 100 different kinds of trees. Our primary forest ecosystem is in the eastern deciduous forest, which is characterized by tall hardwoods such as oak, hickory, poplar, elm and walnut,” True said. “Such diversity in tree species lends itself to an array of different colors as certain colors are characteristic of particular species.”
Hickories, ash, some maple and some oaks, such as white and chestnut, yellow poplar, black cherry, sycamore and sassafras will have leaves that will be yellow and orange in autumn, True said.
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