The severe drought that has impacted much of Minnesota this summer has stressed out many of the state's trees, which will likely mean fall foilage will pop earlier this year.
"The drought has already had an impact," Val Cervenka, the Minnesota DNR's forest health program coordinator, told Bring Me The News on Wednesday. "I have reports of leaves already changing color."
That's much earlier than normal.
While "peak fall color" is variable, the bold, vibrant reds, oranges, and yellows that decorate Minnesota's landscape usually don't peak until mid-September to early October in most of northern Minnesota. In the Twin Cities and central Minnesota, it's typically in late September to mid-October.
"With things changing already — I've heard of sumac already changing, I've heard of birch already changing — it is just going to happen earlier," Cervenka said. "In general, that's what's going to happen in a drought."
Exactly when colors will peak is still TBD.
Cervenka said it's "kind of impossible" to predict when areas of the state will hit peak color. "Average peaks are kind of known, but what does that mean in a year like this year? It's kind of a 'wait and see how it's going to turn out.'"
There is a lot scientists don't know about the science of fall colors, and in a regular year, "it's super hard to predict fall color," Cervenka said. Although, in a normal year, "We can say, 'It's going to be fantastic' because we have such a big variety of trees coupled with our lakes and rivers, so it's pretty easy to say every year that it's probably going to be awesome."
"A year like this, we can say 'There might be pockets of awesomeness but they might be fewer and not as obvious as they have been in your favorite leaf-peeping areas,'" Cervenka explained. "It's really a wait-and-see for a lot of things. Prepare to be surprised!"
That being said, it's not going to just be "a blanket brown cover," she said. "Everything is not just going to be awful. There are going to be pockets where trees have survived better than others."
While much of Minnesota is still in extreme or severe drought (as of Aug. 3), southeastern Minnesota has recovered some. Much of the area is in a moderate drought, while along the Minnesota-Wisconsin border, it's abnormally dry or is experiencing no drought at all.
"There's definitely going to be some color [in southeastern Minnesota]," Cervenka said, noting places where trees have been able to get adequate moisture is "probably going to be glorious."
That's one of the areas Cervenka suggests checking out this year. When people think of leaf-peeping, they typically think of driving north but Cervenka says southeastern Minnesota is a great place to seek out fall colors this year.
"In Minnesota, we don't have mountains but we do have changing elevation, like along the bluffs in southeast Minnesota and in the Arrowhead region there's a lot of changing topography, and with that comes a lot of great color change," Cervenka said. "So those kinds of areas, where there's lots of varying topography, will be good places to check out."
Cervenka did note that on the North Shore and in the Arrowhead, the soil is shallower, which can cause trees to be impacted more quickly by drought, so expect the colors there to change faster and "maybe not be as brilliant."
Get out and explore
Cervenka says just because the drought will likely impact this year's fall colors doesn't mean you shouldn't get outside and enjoy all Minnesota has to offer.
"There's going to be color and there are other things to look at and do besides taking photographs of beautiful leaves," Cervenka said.
Among the other things to look for this fall are native grasses and flowers, trees with berries, as well as fall mushrooms that are "colorful and interesting," and will pop up with a little rain. So maybe you'll be "looking down this year instead of up," Cervenka said, adding that you shouldn't eat any mushrooms you find unless you "very much know" what you're doing.
"Almost more than looking at something is the great feeling you have walking outdoors in the fall, especially after this long, hot summer. It's going to be a relief just to get out there in the fresh air and be in cooler air," Cervenka said. "Even a rainy day, because it's going to be so welcome, that's not going to turn people away from getting out."
Plus, many Minnesota State Parks have lakes, rivers and streams, providing beautiful vistas, that will look so "refreshing" after this summer, Cervenka said.
"If we are seeing pockets of beautiful, vibrant color, that's going to be the bonus this year," she said. "The main thing is going to be getting out — it's good for us physically, it's good for our mental health to be out."
Cervenka suggests visiting a state forest or state trail that you've never been to, noting many state forests offer "beautiful vistas" and fall colors people may not see in the State Park they're used to visiting.
Why does a drought impact fall colors?
Weather is critical to determining the colors trees display each fall, and are best when high-quality foliage (the leaves the grow during a warm, moist summer) are exposed to sunny, cool fall days, the Minnesota DNR says.
Physiological stresses on trees impact their fall colors, and while a mild drought can help increase a tree's color display, a severe drought usually dulls the colors noticeably — in some cases, leaves may die early or turn straw-colored due to lack of water, leading to a more subtle color display in the fall, the DNR states.
So why is this? Well, simply put: trees need water to survive.
During a drought, the soil will hold moisture where a tree's fine roots can't get at it (this is why trees in shallow soils are more susceptible to drought and become stressed easier), Cervenka explained. And in order to cope with the lack of water, a tree will get rid of the part of them that loses a lot of water — their leaves.
Water is lost constantly through leaves and is replaced by rain, but in a drought when there's little to no rain, trees shed their leaves to conserve water, Cervenka said. Leaves on trees and shrubs may also curl and get scorched instead of dropping their leaves. When this happens, those leaves won't turn green again before dropping.
That's why during drought years fall colors may peak earlier than normal, as well as dull the colors the tree produces.
When a tree has green leaves, it's producing energy for itself through the process of photosynthesis (the leaves collect energy from the sun). But when a tree drops its leaves – or if the leaves get scorched – the tree can no longer go through photosynthesis, so there is no more energy production and the tree goes into dormancy, Cervenka said.
This is what trees do in the fall in preparation for winter, but trees trying to cope with drought may go into dormancy early, hence why you may see some leaves turning color already.
Cervenka says the effects of this summer's drought won't be known until next year — the tree will either bounce back or it may have died. Droughts are stressful on trees, which also makes them vulnerable to insects and diseases, which can harm and kill trees.
Thankfully, Cervenka says, there have been little bursts of rain as of late, which will on the surface help stabilize trees. However, it won't be enough to dramatically improve the fall color outlook this year.