By Amanda Sears
Remember jumping into a pile of leaves as a kid? Or running through the fallen leaves and kicking them up as you go?
Fall provides us with a wonderful time to enjoy the outdoors, but why do the trees change color and lose their leaves?
There are several factors that contribute to the change in leaf color. The one that remains the same from year to year is the shortening day length.
The other factors, which can vary from year to year, are weather and levels of pigments present in the leaves.
Leaves are naturally green because they contain chlorophyll, which traps light and converts it into energy for the tree. As the temperatures change and the days start to get shorter, the leaves begin to shut down this food making process.
The color yellow we see in the fall was always present in the leaf. It was just masked by the green of the chlorophyll. The chemical creating the color yellow is also found in carrots, called carotene. It is much more stable than chlorophyll, so it remains once the other breaks down in the fall.
Other colors, such as red, purple and orange are due to other chemical changes occurring in the leaves, and are linked to the acidity of the leaf sap itself, and occur after the leaf begins to die.
Weather also affects the intensity of the colors in the fall. The brightest colors come after a warm dry summer with early autumn rains. A lot of rain in fall can lead to drab coloration. Ideal fall conditions are warm sunny days followed by cool nights with temperatures below 45 degrees F.
So get out and enjoy the fall weather. In another week or so we should be seeing some beautiful fall colors.
Correction: In last week’s article I said that the Farm City Banquet speaker Tammy Horn worked for the University of Kentucky. She is actually a research bee specialist at Eastern Kentucky University.
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