Statewide Forest Health

2025 DNR Spongy Moth Spray Plans Announced

Photo showing an airplane spraying pesticide over trees at Devils Lake State Park in Sauk County to help in the control of spongy moth caterpillars.

An airplane sprays pesticide over trees at Devils Lake State Park in Sauk County to help in the control of spongy moth caterpillars. / Photo Credit: Sue Johansen, Wisconsin DNR

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

The Wisconsin Department of Natural Resources (DNR) has finalized aerial spraying plans for its 2025 Spongy Moth Suppression Program, with maps for the five selected treatment areas available online.

The treatment sites are at three state parks in Juneau, Marinette and Sauk counties that are highly valued for their recreational use. A total of 544 acres of trees will be treated with an aerial spray of “Foray” bacterial insecticide containing Bacillus thuringiensis var. kurstaki.

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April Offers Opportunities For Tree Lovers

Wide-angle photo showing that a beautiful view of Wisconsin forestland awaits visitors to Roche a Cri State Park in Adams County.

A beautiful view of Wisconsin forestland awaits visitors to Roche a Cri State Park in Adams County. / Photo Credit: Wisconsin DNR

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

“Acts of creation are ordinarily reserved for gods and poets. To plant a pine, one need only own a shovel.”

Those were the words of Wisconsin’s most prominent conservation expert, Aldo Leopold, who authored the famous book, “A Sand County Almanac” among his many achievements.

This month, everyone in Wisconsin will have the chance to follow Leopold’s advice – even if in a small way, because many small efforts can add up to a prominent positive impact on Wisconsin’s trees and forests.

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Watch For Oak Decline And Mortality This Summer

Oak decline and mortality at Big Foot Beach State Park in 2024.

Oak decline and mortality at Big Foot Beach State Park in 2024. / Photo Credit: Wisconsin DNR

By Michael Hillstrom, DNR Forest Health Specialist
Michael.Hillstrom@wisconsin.gov

Oak decline and mortality continue to be an issue in Wisconsin, and because of the recent droughts and spongy moth outbreak, we expect these impacts to become more widespread this summer.

Forest decline is the progressive loss of tree and stand vigor and health over several years without obvious evidence of a single causal factor. Typically, trees die in a scattered fashion across a large area over several years. The additional stress from defoliation can result in pockets of heavy oak mortality, particularly on dry, sandy sites and steep, rocky ridges and hills.

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Urban Forest Inventory And Analysis Release

By Dan Buckler, DNR Urban Forest Assessment Specialist
Daniel.Buckler@wisconsin.gov or 608-445-4578

Much of what we know about our urban forests is limited to publicly maintained spaces such as in parks or along streets. However, the curtain covering other urban lands is rising, starting in Milwaukee and Madison.

The Urban Forest Inventory and Analysis (UFIA) program, a partnership between the USDA Forest Service and the DNR, has established 1,300 permanent plots in urban areas across Wisconsin. Project foresters captured loads of information on each plot, such as tree species and sizes, land ownership, tree damages, and wood volume. The data were extrapolated from those plots and made into estimates for each city. The data were also incorporated into i-Tree to calculate ecosystem services. Continue reading “Urban Forest Inventory And Analysis Release”

A Hopefully Not-Too-Deep Look Into i-Tree Benefits

By Dan Buckler, DNR Urban Forest Assessment Specialist
Daniel.Buckler@wisconsin.gov or 608-445-4578

Trees work in mysterious ways, and, for some users, so does i-Tree. The suite of software, developed by the USDA Forest Service and Davey Tree Expert Company, can, among other things, calculate the societal benefits of trees. Below, I try to summarize and demystify some of these estimates of ecosystem services, a somewhat sterile term for some of the cool things trees do for society and the wider environment.

Because the benefits identified in i-Tree only scratch the surface of trees’ importance to one’s community, it could be problematic and limiting if estimates from i-Tree are solely relied on to justify the investment in tree preservation, maintenance or planting. Nonetheless, these estimates help tell the story of the good work trees do in our communities. Continue reading “A Hopefully Not-Too-Deep Look Into i-Tree Benefits”

Spring Brings Opportunities To Protect Oak Trees

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

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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Squirrel Or Porcupine Damage: How Do You Know?

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

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

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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