The fall foliage is hitting peak colors this week in the North Carolina mountains. The rest of the state will follow over the next couple of weeks. Experts say it appears to be a good year, with intense colors coming at what used to be a normal time — mid-October. But that's been slipping later because of global warming.
"This is a great year," said Howard Neufeld, a biologist at Appalachian State University who posts on Facebook as the Fall Color Guy. "We're at peak right now here between Blowing Rock and the Linn Cove Viaduct/Grandfather Mountain area, and also in Highlands and any place on that elevation level."
"The colors are just about the brightest I've ever seen," he said. "The yellows are even brighter. And especially the reds this year are really, really bright, especially the ornamental maples that are in Boone and other cities."
With that said, this year may be a bit of an outlier compared with other recent years and future trends.
"Every year is going to be a little bit different. I mean, that's just the way things are. But on average, over the past 60 to 70 years, every decade results in a four-day later peak fall," said Jeff Gillman, director of the UNC Charlotte Botanical Garden.
Gillman said several complex factors affect fall colors: autumn's shorter days, temperatures and stress, such as a lack of rainfall. The latter two are most important, and are key effects of global warming, he said.
Fall colors emerge when it starts to get cool. In recent years, it has turned cool later. As Nuefeld pointed out, it got cool earlier this year, so we're having a more normal year — at least compared to the "normal" going back a generation.
But it's staying warm later and later into fall and we're experiencing droughts more often in summer, which is pushing fall colors later into October and November.
Neufeld has been tracking the arrival of autumn leaves in the Boone-Blowing Rock area for 15 years.
"For nine years from 2008 to 2016 with one exception, it fell about this time of year, every single year," Neufeld said. "After 2016, it started getting really delayed. With the exception of one year, 2020, which was on time, all the rest were very delayed. And in 2019, it was two weeks late. And those years were associated with a lot of warming."
He said that will be the trend in the future, as the planet keeps warming.
"If we're going to have substantial warming, it's going to delay the fall colors. It'll (also) probably dull them and reduce the impact," he said.
As we've said, leaves change color in response to shorter days, cooler temperatures and dry conditions — all characteristics of fall. But when those deviate from normal, the colors may not be as bright.
The climatic changes have another interesting effect, according to Neufeld — a longer leaf-peeping season.
Some trees, like dogwood, respond more to shorter days than weather changes. So they might turn colorful on one schedule, while other trees waiting for cool weather might change much later.
"It'll spread out the fall color season. And when you do that, then you don't have as many trees coming into color at the same time. So it doesn't quite look as vibrant on the landscape," Neufeld said.
"And if it gets warmer and it gets drier, then you may have trees like the tulip poplars and some other sensitive species just drop their leaves early. Then you wouldn't have their color, either. So that's kind of how I look at what might happen in the future," Neufeld said.
Meanwhile, increasing carbon dioxide from pollution may also be a factor, Neufeld said. "There's some evidence that rising C02, which is what's causing global warming, actually will delay the onset of fall color so that trees will stay green later into the season."
Over the long term, though, there may be some hope for the blazing fall displays we love. Neufeld said some tree species may begin to migrate north to cooler areas, which means the fall show will move.
So what fall colors do the experts prefer?
Neufeld: "I'm partial to the sourwood, which has really deep purple leaves and has those white seeds that sort of splay over the red leaves. So you get red and white together at the same time."
Gillman: "I have a lot of trees I like to watch but the ones that I like best are going to be not a tree — the oak leaf hydrangea can develop some really wonderful colors. I certainly love the various Japanese maples, they can have various colors. Red maple, of course, is great, too."
And by the way, the climate factors that delay the onset of fall are also at play all year. Climate change also means shorter winters and earlier springs in our region.
READ MORE
- For a tourist's guide to fall colors, see the fall foliage prediction map
- See also Howard Neufeld's "Fall Color Guy" page on Facebook and his analysis of the science of fall colors
- And here's a guide to the seasonal changes at UNC Charlotte's Botanical Garden
This article originally appeared in WFAE's weekly Climate newsletter, published Thursdays. Don't miss the next one!
