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LETTERS FROM LOCKERLY: The science and spirit of fall color
Published 11:10 am Thursday, December 18, 2025
As the heat of summer levels off, days grow shorter and shadows stretch across a changing landscape. Fall color may be a slow burn rather than a blaze in Middle Georgia, but it is nonetheless beautiful.
Trees don’t own calendars.
So how do they know when to change colors? Shorter days and cooler nights signal trees to stop producing chlorophyll, the green pigment that drives photosynthesis, the process by which plants convert light into usable energy.
The chlorophyll already present in a tree’s leaves breaks down into simpler compounds that are reabsorbed. As it fades, yellow and orange pigments that were there all along are revealed. While it may seem like an addition, it is actually a subtraction that allows these hues to appear.
Red and purple tones, on the other hand, are specially produced by some species. Scientists believe these pigments may deter certain insect pests or act as a protective “sunscreen,” preventing sun damage so trees can reabsorb as many nutrients as possible before the leaves fall to the ground.
No two autumns are the same. Weather conditions, particularly temperature, moisture and light, play a major role in the quality of the color display.
Red pigments are enhanced by cold yet sunny days. Heavy rain or wind can knock leaves off early, and summer drought can stress trees, causing them to shed their leaves prematurely.
Fall color may also be more intense in some regions due to the composition of trees. A high proportion of evergreen conifers, like pine trees, keeps the forest green year-round and can mute the overall display, while areas with a greater diversity of deciduous hardwoods produce a broader palette.
At the arboretum, the show unfolds gradually from late October through late November. Our abundant native sweetgum trees lead the season with a rainbow of yellow, orange, red, and purple, often all on the same leaf. Red maples and blackgum follow with crimson canopies in the Anne King Native Plant Garden.
Visitors walking along the Nature Trail can also spot the gold-bronze leaves of American beech and the coppery hues of bald cypress along the pond.
I try to take cues from the trees as they prepare for winter. I slow down, take time, and appreciate the tapestry of living things all around us.
Autumn may arrive gently in Middle Georgia, but that gives us time to notice the quiet changes taking place, and we invite you to experience them here at Lockerly Arboretum.
—Carter Payne is a horticulturist at Lockerly Arboretum. He can be reached at [email protected].
