Month: March 2025

DNR Urges Spring Spongy Moth Treatment Plans

Posted on by akabelowsky
Carefully scraping spongy moth egg masses off trees and into a cup of soapy water will help to hold down caterpillar damage in 2025.

Carefully scraping spongy moth egg masses off trees and into a cup of soapy water will help to hold down caterpillar damage in 2025. / Photo Credit: Bill McNee, Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist
Bill.McNee@wisconsin.gov or 920-360-0942

The Wisconsin Department of Natural Resources (DNR) encourages property owners to examine their trees for spongy moth egg masses and determine whether control measures are needed this spring.

Property owners who have oak, birch, crabapple, aspen, willow and linden (basswood) trees should be particularly watchful because the caterpillars of this invasive insect prefer these species. However, they will feed on many other kinds of trees and shrubs.

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Spring Brings Opportunities To Protect Oak Trees

Posted on by akabelowsky
A photo of an oak tree with a branch that has been pruned, but not treated with protective paint to prevent infection with oak wilt.

Pruning, cutting, or wounding oaks during April through July leaves them vulnerable to oak wilt. / Photo Credit: Paul Cigan, Wisconsin DNR

By Paul Cigan, DNR Forest Health Specialist
Paul.Cigan@wisconsin.gov or 715-416-4920

With warmer spring weather fast approaching, the Wisconsin Department of Natural Resources (DNR) recommends protecting oaks from the often-fatal disease, oak wilt, by refraining from pruning, cutting or injuring oak trees from April through July.

Oak wilt is a serious disease that kills trees in the red oak group (including pin oak, northern red oak and black oak) and weakens those in the white oak group (bur oak, swamp white oak, white oak and English oak).

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Treat Ash Trees Against Emerald Ash Borer This Spring

Posted on by akabelowsky
A photo of an ash tree next to a park trail in Winnebago County showing damage from woodpeckers feeding on EAB larvae beneath the bark.

An ash tree next to a park trail in Winnebago County shows damage from woodpeckers feeding on EAB larvae beneath the bark. / Photo Credit: Bill McNee, Wisconsin DNR

By Bill McNee, Forest Health Specialist
Bill.McNee@wisconsin.gov or 920-360-0942

Property owners with healthy, valuable ash trees are encouraged to treat them with insecticide this spring to protect against emerald ash borer (EAB).

The invasive pest is currently the most damaging threat to trees in Wisconsin, killing more than 99% of the ash trees it infests.

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Squirrels Can Damage Trees During Late Winter

Posted on by akabelowsky
Photo showing that squirrels have removed significant amounts of bark from a maple tree's trunk to get at the tasty cambium layer underneath.

Squirrels have removed significant amounts of bark from this maple to get at the tasty cambium layer underneath. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, DNR Forest Health Specialist
Linda.Williams@wisconsin.gov or 920-360-0665

Squirrels can be fun to feed and fun to watch, but when they start damaging or killing your trees, well, that’s not so cute.

It’s the time of year when we start to have some warm days that allow sap to start moving in trees. If there are broken branches or damaged bark, the tree can drip sap. And that can attract squirrels.

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Squirrel Or Porcupine Damage: How Do You Know?

Posted on by akabelowsky
Photo showing squirrel tooth marks on a tree. Squirrel tooth marks are small and look like narrow scratches where the animals have removed the tree’s bark.

Squirrel tooth marks are small and look like narrow scratches where the animals have removed the tree’s bark. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, Forest Health Specialist

Linda.Williams@wisconsin.gov or 920-360-0665

If something chewed the bark off your tree, how would you go about determining the culprit?

Quite a few animals can damage bark on trees, from deer and bears to rabbits and mice. But the damage from squirrels and porcupines can look very similar, especially from a distance. So, how can you tell the difference?

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Heterobasidion Root Disease Online Maps Updated

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Photo of a tree showing fruiting bodies of Heterobasidion root disease at its trunk.

A tree shows fruiting bodies of Heterobasidion root disease at its trunk. / Photo Credit: Wisconsin DNR

By Kyoko Scanlon, DNR Forest Pathologist
Kyoko.Scanlon@wisconsin.gov or 608-235-7532

Heterobasidion root disease (HRD), a destructive fungal disease, continues to be found in Wisconsin.

The Wisconsin Department of Natural Resources (DNR) has confirmed detections in several stands over recent months.

The DNR’s 6-mile and 25-mile buffer zone maps have been updated based on the locations of the newly confirmed stands. The most notable changes due to expanded buffer zones have taken place in Door, Marinette, Milwaukee and Pierce counties.

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Tune In: Forest Health Team In The Media

Posted on by akabelowsky
Photo showing DNR Forest Health specialist Paul Cigan looking for various species of invasive plants during a visit to a bog at the Wisconsin Department of Natural Resources' Kemp Research Station

Paul Cigan looks for various species of invasive plants during a visit to a bog at the Wisconsin Department of Natural Resources’ Kemp Research Station on Tuesday, June 25, 2024. / Photo Credit: Art Kabelowsky, Wisconsin DNR

By Art Kabelowsky, DNR Outreach and Communications
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

Paul Cigan, the Wisconsin Department of Natural Resources’ (DNR) forest health specialist for the northwest zone, recently appeared on the Ventures of the Land podcast, hosted by George Atwell, to discuss oak wilt’s past, present and future in Wisconsin.

The talk included details on how and when the invasive fungal disease arrived in the state, how it attacks oak trees and methods landowners can use to manage the disease.

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Mary Bartkowiak Retires As Forest Invasive Plant Coordinator

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Photo showing Mary Bartkowiak, the Wisconsin Department of Natural Resources' recently retired Forestry Invasive Plants Coordinator, giving a presentation on invasive plants at the University of Wisconsin's Kemp Natural Resources Station in Woodruff.

Mary Bartkowiak, the Wisconsin Department of Natural Resources’ Forestry Invasive Plants Coordinator, gives a presentation on invasive plants at the University of Wisconsin’s Kemp Natural Resources Station in Woodruff on June 25. / Photo Credit: Art Kabelowsky, Wisconsin DNR

By Art Kabelowsky, DNR Outreach and Communications
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

It seems quite fitting that a natively grown expert has spent much of the last 15 years of her career fighting the expansion of invasive plant species in Wisconsin.

Mary Bartkowiak, a Wisconsin native who joined the Department of Natural Resources (DNR) in 2010 and has served as the Forest Invasive Plants Coordinator since 2020, announced her retirement in February.

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