This week is likely the last opportunity to see peak fall foliage in Central Illinois before the bitter cold of winter moves in and the trees become bare.
Environmental factors combined to create a leaf-viewing season that local experts say is one of the more memorable in recent years.
As a scientific refresher, leaf color changes from green to vibrant hues of yellow, orange and purple when dropping temperatures and limited sunlight give trees the signal to begin breaking their chlorophyll down for the winter.
“There’s something called carotenoids that are in there and they’ve been in there the whole season, kind of behind this chlorophyll scene and they’re going to start breaking down too,” said Nicole Flowers-Kimmerle, horticulture educator for the University of Illinois Extension. “But they break down slower. So the green kind of fades away, and you start to see that yellow that’s just that being expressed.”
Flowers-Kimmerle says some of the sugars in certain trees are broken down into anthocyanins, which create the brighter reds and purples of fall. Colors vary by species. Maples, which Flowers-Kimmerle says are common in this area, tend to show reds and oranges. Red Oaks are, predictably, red. Black Gums and Sweetgums boast an array of colors.
It’s not just the trees either.
“We also have shrubs with beautiful coloring, dogwoods, and, let’s see, burning bush, although that one’s considered invasive, but it’s still got a beautiful fall color,” Flowers-Kimmerle said.
There are three environmental factors that Flowers-Kimmerle says play a role in the length and quality of our fall foliage season. Those are day length, temperature and moisture.
“When it is very dry, sometimes we will see that leaves are going to fall off before we get a bright color, because they don’t really have enough resources to do that transition,” Flowers-Kimmerle said.
Though this August and September were dry in Illinois, the leaves stuck around long enough for a brilliant display. Peoria Park District Supervisor of Park Horticulture and Recreation Maintenance Jacob Kuban says those other factors, day length and temperature, are likely responsible.
“The capturing and trapping of those sugars is best done when there are warm, sunny days and cool, crisp nights, but not freezing, just above freezing,” Kuban said. “Which we’ve had a lot of that, the past couple weeks and I think we’re going to continue to have those.”
Kuban has been with the Peoria Park District for eight years. He says this fall foliage season would rank high in the middle of all the ones he’s seen so far.
“They don’t really have it narrowed down, like, specifically, how much soil moisture, you know, rainfall we need to have a great fall color and that’s because of the diversity of species,” Kuban said. “Some things do better in certain years and some things don’t.”
Kuban believes Detweiler Park, heading out of Peoria along the riverfront, is the best on offer for leaf viewing. There’s a wide variety of trees there, including more than 100 acres of sugar maples, oaks, hickories and walnuts. There are also a few exotic trees here and there, including a stunning yellow Ginkgo tree at one of the park entrances.
“We specifically open up a section of road at Detweiller for fall color, viewing and driving and walking, bicycling, just to enjoy those fall colors,” Kuban said. “It’s great because of the species diversity of trees here.”
Driving the stretch of road throughout the park takes roughly ten minutes and includes a variety of views. Leaves of all colors create a tunnel of foliage that stretches in every direction as far as you can see.
“I would say, just embrace the nature’s beauty,” Kuban said.
Kuban also recommends Robinson, Tawny Oaks, Singing Woods, Donovan and Glen Oak parks as prime for leaf viewing. If you’re going to go though, you should do it soon, Kuban expects this week to be the last peak for colors.
