Drought shouldn't dry up fall color season, DNR experts say
Sep. 7—GRAND FORKS — Much of northwest Minnesota and northeast North Dakota are in moderate to severe drought, but the dry conditions won't necessarily have a significant effect on fall colors, experts from the Department of Natural Resources say.
Other weather factors, such as an early hard freeze — if it was to occur — would have a larger impact.
"We haven't seen any obvious effect (from drought) on our fall colors in recent years," said Brian Schwingle, a DNR forest health specialist. "We've had some drought, but there isn't an obvious correlation. Maybe the brilliance of fall colors diminish across the landscape, but not at a level that most people would notice."
Schwingle was among three DNR panelists to share insights on the upcoming fall color season during a virtual presentation for members of the media Thursday afternoon, Sept. 7. Other panelists were Sara Berhow, public relations supervisor for DNR Parks and Trails; and Kenny Blumenfeld, a DNR climatologist.
Day length and genetics are the primary drivers of fall colors, Schwingle said. As day length decreases, trees stop producing chlorophyll, the green pigment crucial for photosynthesis. When that occurs, other pigments — such as yellows, oranges and browns — already in the leaves become more visible.
At the same time, genetics mean trees such as maples turn color before others such as tamaracks, Schwingle said.
Carotenoid compounds, which also give carrots their orange color, produce the yellows and oranges in leaves of deciduous trees such as aspen, while another set of compounds known as anthocyanins produce the reds and purples in maple trees.
"It really is all about unmasking the pigments that are already there," Schwingle said. "They've always been there, it's just that there's so much green chlorophyll that it covers them up during the spring and summer."
Weather factors such as rain, wind, overcast skies, drought and temperature all can affect the timing, duration and brilliance of fall colors, he said.
"The biggest weather factor that no one wants in the Upper Midwest is a really hard, early freeze," Schwingle said. "That can halt the physiological fall color process in its tracks and make green leaves just drop off trees like crazy."
Brilliance, he says, is "kind of a subjective term" when it comes to fall colors.
"It's really tough to determine how brilliant fall colors are," Schwingle said. "Just from my perspective as one person in Minnesota, they're pretty good every year."
Blumenfeld, the DNR climatologist, said Minnesota is in the fourth straight year of very dry conditions during the growing season and the third straight year in which those conditions have led to significant drought categories. Each of the last three years has had at least extreme drought in Minnesota, he said, and two of those years — 2021 and this year — have reached the "exceptional" category, the U.S. Drought Monitor's highest level of drought.
Two small areas, one west of Duluth and the other in far southern Minnesota near the Iowa border, are now in the "exceptional" category, Blumenfeld says.
"Smaller and smaller parts of the state are experiencing no drought currently, so this has been the big story," he said.
As for the impact of that drought on fall colors, "the waters are very muddy," said Schwingle, the DNR forest health specialist.
"Certainly the more droughts we get in a row, the greater the stress on trees," Schwingle said. "When a given tree is severely drought-stressed, what it does in the summer is it drops a lot of its leaves, and a lot of its leaves turn brown."
A "really severe" drought will diminish the brilliance of fall colors, he says, while a moderate drought will delay the onset of those colors.
Some scientists, however, say drought actually enhances fall colors, Schwingle says.
"It's a very complicated process, and I don't feel like anyone truly has a firm grasp on it," he said.
Currently, most of Minnesota is in the 0% to 10% fall color category, except for a small area of far northwest and western Minnesota, where colors are in the 10% to 25% range. In far northern Minnesota, fall colors typically peak in mid- to late September, while mid-September to early October generally is peak time in northwest Minnesota.
The DNR posts
fall color updates on its website
every Wednesday, based on reports from state park staff across the state. People can also sign up for a free fall color update newsletter, set to launch in mid-September, on the DNR website. The website also offers a place for people to share their fall color photos.
With 75 state parks and recreation areas, 59 state forests and 27 state trails covering 1,300 miles, there's no shortage of options for getting outside on public land in the fall, said Berhow, the DNR's Parks and Trails public relations supervisor.
"Really, at the DNR, we want to say, 'Come explore outside in the fall,' " she said. "The temperatures are comfortable, there's fewer mosquitoes — it's just a great time to be outside.
"Whether people are seasoned outdoors people or new to outdoor recreation, there are lots of different places to go and things to do."
For more information on fall colors, check out the
Fall Color Finder
on the DNR website at
to sign up for weekly email or text updates.
In North Dakota, check out the North Dakota Tourism Department website at
and scroll down to the
"Best Places To View Fall Foliage in North Dakota"
link.
