The vibrant red, orange and yellow leaves of Wisconsin’s autumn color show are not far away.
According to Colleen Matula, a forest silviculturist and ecologist with the state Department of Natural Resources, those in the Chippewa Valley can expect peak fall colors to begin anytime from next week to mid-October. Travel Wisconsin’s interactive Fall Color Report says Eau Claire County is seeing about 15 percent coloration, with an expected peak in the third week of October.
Chippewa, Trempealeau, Buffalo, Dunn and Jackson counties are seeing similar color reports from 15 to 20 percent, according to the report.
Northern Wisconsin counties will see, as usual, an earlier peak for leave coloration, Matula said. The Fall Color Report shows Douglas County is already seeing 60 percent coloration, and Iron County sits at about 50 percent. Matula anticipates that region’s peak to be by the end of this week, with surrounding counties seeing 20 to 30 percent coloration as well.
But there’s no way to predict exactly when peak will be, Matula said, as it depends on the area’s weather conditions this month and next.
What causes the coloration in the first place is the amount of light the trees get, Matula said. As the days get shorter, the trees receive less light, which causes the leaves’ chlorophyll production to shut down.
The colors of leaves come from different pigments.
Chlorophyll is what gives leaves the typical green color and is the most important, as it allows for photosynthesis. Carotenoids produce bright yellow, orange and brown colors. Carotenoids are what color corn, carrots and bananas throughout the year and are always present in aspen and birch trees, which is why they have more predictable coloration each year, according to the DNR.
Anthocyanin, which produces red and purple leaf tints, is what colors cranberries, red apples, cherries, strawberries and more. The presence of anthocyanin varies from tree to tree depending on overall conditions, which is what makes each fall unique.
Another factor that may impact leaf coloration is rain. If the area receives a significant amount of rain, the leaves may blow off or fall off, which may affect the leaf volume and the overall health of the trees. The less healthy a tree is, Matula said, the less likely it is to produce a stunning autumn color show.
Rain can also cause trees to develop fungal diseases, which may cause decreased coloration. Significant rain last year led to the development of fungus in many trees. Along with an outbreak of the leafminer insect in several regions of the state, Matula said, many remarked of a more dismal fall color display last year.
The same issues may bode the same result this year, Matula said, as DNR officials are noticing issues with aspen and birch trees across the state.
“Leaves are already starting to prematurely fall off, and that can affect the whole array of colors,” she said.
Leafminers feed on the tissue between the upper and lower epidermal layers of leaves, according to a UW-Extension article about Birch leafminer. When a tree becomes infected with the insects, leaves may turn brown and papery, then will fall off the tree.
Matula also noted that if temperatures dip and regions see heavy frost, that may cause leaves to fall early.
The Weather Co. predicts Eau Claire will see partly cloudy skies every day of the workweek except Thursday, when there is a slight chance of showers. High temperatures are expected to be 72 degrees today, 61 Tuesday and 58 Wednesday through Friday. Lows are expected to stay above freezing.
For more information on Wisconsin’s autumn colors, contact the DNR Department of Tourism’s Fall Color Hotline at 800-432-TRIP, or view Travel Wisconsin’s Fall Color Report at travelwisconsin.com/fall-color-report#.
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