The majesty of fall leaves never gets old.
And for the next two weeks, the foliage in northern Georgia will be as multi-hued as an Andy Warhol painting – albeit with more autumnal shades.
So maybe you’re wondering why some years the trees – whether blanketing the Blue Ridge Mountains or decorating the office parking lot -- seem more vibrant than others.
Chalk it up to weather.
According to Dr. Matthew Weand, a forest ecologist who teaches plant biology and botany at Southern Polytechnic State University in Marietta, the optimal conditions for color development are bright, sunny fall days with moderate nighttime temperatures (in the 30s and 40s). Under those conditions, non-chlorophyll pigments and sugars stay in the leaves longer, so color development is stronger.
But it might already be too late by the time fall weather arrives.
George Bain, forest supervisor for Chattahoochee-Oconee National Forest, noted that because Georgia experienced such a dry summer, that lack of moisture results in duller colors.
“It’s not going to be one of our more brilliant years,” Bain said. “Some of the reds and oranges aren’t going to show up and the leaves will turn brown a little quicker. There are still a lot of yellows up there and you’ll see some of the darker reds on the oaks, but the brilliant oranges from the maples won’t be quite as bright.”
Still, there is plenty of natural beauty to ogle at the nine overlooks along the national forest roads and in the mountains of north Georgia, where the most vibrant shades are expected to blossom between now and Oct. 29.
The Atlanta area typically lags about a week behind the northern part of the state.
And Bain does caution drivers to be cognizant of, well, driving instead of looking out the window to admire the foliage.
While veteran leaf peepers understand the science behind the gradual shifting in color, most of us take the annual act for granted, even getting irritated when the bright reds and yellows don’t appear fast enough or long enough.
Sorry, but you can’t challenge nature.
“What a lot of people don’t realize is that the color change is an active process that the tree is orchestrating. The leaves aren’t simply dying and falling off – the resources are being absorbed back into the tree,” Weand said.
Once the weather turns cooler and sunlight pulls in earlier, chlorophyll, the green pigment in leaves, begins to break down and is reabsorbed by the tree. That means other pigment molecules, such as carotene and xanthophyll, the ones responsible for yellows and orange-red color, become visible.
“It’s a physiological process,” Weand said. “Once the cues are in place, the plant proceeds to work through that and you’ll see fall colors that will last over a month.”
Trees with the brightest leaves
Sugar maple – red
Beech and birch – yellow
Hickory (shagbark and bitternut hickory) -- yellow
Red oaks – yellow to red
Red sweetgum – yellow, purple or red
Further information:
Fall color hotline: 800-354-4595
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