It’s still too early to tell just how brilliantly colored the autumn leaves will be this year, but Clemson University’s forest ecologist Donald Hagan says there’s potential for a spectacular season.
The weather over the next few weeks will help put the finishing touches on the color palette, Hagan said.
“A lot of that is going to be dictated by the weather that we get over the next several weeks as we transition from summer into fall. If we have typical weather – if we have this succession of mild cold fronts that kind of gradually ease us into fall, that’s going to be good. That should lend itself to really good fall color,” he said.
The early autumn weather cycles, where there’s a cold front and perhaps some rain, followed by mild days with deep blue skies, help to trigger the fall color development.
“Those clear, bluebird skies, when you have that cool, or milder fall weather, those two factors really trigger fall color development,” Hagan said. “One thing, the cool weather starts to flip the switch on these plants and let them know that, ‘Hey, winter is coming. It’s time to get ready to go dormant.’ And then you have that clear weather, a lot of that color change, particularly the reds and the purples, the development of those colors is triggered by sunlight.”
But severe weather in the next couple of weeks would likely swing the pendulum in the other direction. An intense wind event would blow leaves off trees, and an early frost could end the season early, he said.
While the Blue Ridge Parkway is almost invariably awash in bright colors in the autumn, Hagan also enjoys seeing what autumn brings at Table Rock State Park.
“Table Rock State Park is a really great place because you can be right there on Highway 11 and look off towards the park, and Table Rock is well over 3,000 feet high,” he said. “So you’ve got a couple thousand feet of elevation change right there. And as you get into mid- to late-October, you can see the fall color kind of spilling down the mountain, so … you’re almost guaranteed to see some good color.”
He’s especially interested to see how the 2016 wildfires will impact the colors at Table Rock, because a tree under stress often produces especially beautiful fall colors.
“That entire mountain burned last year. It wasn’t a catastrophic wildfire, in that it didn’t scorch all the trees. Most of the trees that were exposed to that fire are still alive. … Those trees that were exposed to that fire are going to be under just a tad more stress than, say, the trees that weren’t. So it’s going to be interesting to see how that unfolds. I wouldn’t be surprised in places like Table Rock that experienced the fire to see fall color peaking just a tad earlier.”
Every year has different factors influencing the leaf forecast, and last year’s drought and wildfires will undoubtedly make an impact, he said.
As always, the higher elevations will see the changes first, probably in the next couple of weeks, Hagan said.
Then, the color flows downward over the coming weeks.
“In the higher elevations, you’re going to see peak color probably around very early October. And then you can expect to see that peak color moving downhill, or down in elevation, about 1,000 feet a week after about October 1. So peaking in early October at higher elevations … should give us good color in the Upstate very late October, early November.”
Last year’s fall and winter weather also play a role in how the leaves will look a year later. Hurricane Matthew brought rain last October, but for the remainder of fall and winter, the weather was unusually dry, Hagan said.
The ensuing drought caused trees to enter their annual dormant state under stress.
“This year, our rainfall patterns have been a little bit closer to normal, although towards the end of the summer we started to get some mild drought conditions in some parts of the Upstate. And mild stress is actually a good thing, from a fall color standpoint. It helps condense the fall color season a little more, so you’ve got more species firing off more colors at the same time, which is what people like.”
The yellow poplars in particular have had a difficult time over the past year. The species doesn’t tolerate drought very well, and then the winds of Hurricane Irma blew away many of the leaves that had already begun to change color.
But all things considered, Hagan is optimistic that the coming weeks will be visual delight for fall color enthusiasts.
“It has the potential to be great. I really do think it could be a fantastic year. Some areas are always going to be better than others. I think that’s the fun part, getting out there and exploring.”