Fall colors are expected to peak in the Coulee Region in the first or second week of October, although experts say some trees may look a little peaked because of the wet spring and recent drought.
Although most say color changes are on somewhat of a normal track, in the 10 percent range in the area, the vibrancy remains a question.
The region’s signature bluffs could show erratic hues, with the upper levels less colorful than the lower reaches for lack of water, said Timothy Gerber, an associate biology professor at the University of Wisconsin-La Crosse.
“Water goes downhill, you know, so trees at the top are more stressed,” he said. “Things at the bottom of the bluff do better because they have more water.”
After rainfalls of nearly 8.5 inches in May and almost 6 inches in June that eased last year’s drought, La Crosse limped through July, August and the first part of September with barely
2.5 inches, a pattern that prevailed throughout the region.
Adequate moisture is one leg of the tripod that helps support the biology of color change, with the other two being warm days and cool nights.
“If you stress things, they shut down,” Gerber said. “Some trees have lost their leaves and some have burned, but there still is plenty of green.
“In terms of color, that’s up in the air,” he said. “You’ll see standard color along the river because there is water, but I think things will be more subdued on the bluffs.”
Gerber said he and his students have been out studying plants, and “a lot of trees at Myrick Park look really sad.”
Just returned from northern Wisconsin, Gerber said foliage looked better there.
Adam Zirbel, Wisconsin Department of Natural Resources forester for La Crosse County, said the wet spring spawned fungal leaf diseases in some oaks, which will nullify their colors.
Some trees that look like they are turning actually are showing the results of the diseases, which he said don’t hurt the trees but affect the leaves.
Some walnut, box-elder, maple, elm, birch and aspen trees have begun to drop leaves early, Zirbel said.
On the other hand, he said, “I think it’s going to be a good year for red oaks. The big thing that adds to our color is red oaks, and they will turn the latest.”
Conditions are relatively green, with some slight yellowing, at Perrot State Park in Trempealeau, said park superintendent Jim Thompson.
“I’m hopeful for a really good season,” he said. “I’ve seen magnificent colors on Oct. 1 and in the second and third week of October. Things can change very quickly.”
Across the Mississippi River in Minnesota, “We’re starting to see a little bit of color change,” said Rick Samples, manager of Great River Bluffs State Park southeast of Winona.
Cooler temperatures last week got the cycle going, he said, with ash, cottonwoods and birch starting to turn — “not where they will be, but turning,” he said.
“It could be a good year, depending on the weather, if we got some colder weather,” Samples said.
That is expected to happen, after a couple of warm days this week. Temperatures are expected to drop into the 40s Friday, Saturday and Sunday nights, said National Weather Service meteorologist Dan Jones.
Temperatures next week are expected to be in the 50s overnight and 70s during the day.
“Over the next couple of weeks, we’ll have slightly above normal temperatures,” Jones said.