Did you know?

White Pine Blister Rust Can Devastate Young Stands

Posted on by akabelowsky

By Tim Shively, DNR Forest Health Specialist
Timothy.Shively@wisconsin.gov or 608-772-6974

A close-up photo of a white pine blister rust canker as seen on a young white pine tree.

A white pine blister rust canker as seen on a young white pine tree. / Photo Credit: Wisconsin DNR

Eastern white pine (Pinus strobus) has historically held great ecological, cultural and economic value throughout Wisconsin, a tradition which continues today. For more than 100 years, however, it has been threatened by a non-native, invasive fungal pathogen called Cronartium ribicola, or white pine blister rust (WPBR).

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Impacts Of Winter Weather On Trees

Posted on by akabelowsky

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

A stand of pines shows heavy damage from an ice storm in April 2025.

A stand of pines shows heavy damage from an ice storm in April 2025. / Photo Credit: Wisconsin DNR

Winter damage can significantly impact the health of trees. Keeping trees healthy through the fall is important for reducing winter stress. Provide water as needed to trees until the leaves start falling (for deciduous trees) or until the ground starts freezing (for conifers).

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DNR, DATCP Teams Exemplify Interagency Teamwork

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

Wisconsin Department of Natural Resources Forest Health team leader Becky Gray and Department of Agriculture, Trade and Consumer Protection Pest Survey and Control Section manager Renee Pinski appear before the Natural Resources Board to discuss tree and forest health issues on Nov. 13, 2025.

Wisconsin Department of Natural Resources Forest Health team leader Becky Gray (left) and Department of Agriculture, Trade and Consumer Protection Pest Survey and Control Section manager Renee Pinski appear before the Natural Resources Board to discuss tree and forest health issues on Nov. 13, 2025. / Photo Credit: Wisconsin DNR

The spirit of interagency communication was on display during a joint meeting of the Wisconsin Natural Resources Board (NRB) and the Wisconsin Board of Agriculture, Trade and Consumer Protection (Ag Board) on Nov. 13.

The seven-member NRB is the governing body of the Wisconsin Department of Natural Resources (DNR); the nine-member Ag Board governs the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP). Each board sets policies and rules to be followed and enforced by its respective agencies. Members of both boards are appointed by the governor and confirmed by the Wisconsin State Senate.

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Forest Health Staffers Hit The Airwaves

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Photo of Mike Hillstrom, who became the Wisconsin Department of Natural Resources Invasive Forest Pest Coordinator on Sept. 9, 2024.

Mike Hillstrom became the Wisconsin Department of Natural Resources Invasive Forest Pest Coordinator on Sept. 9, 2024. / Photo Credit: Wisconsin DNR

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

Mike Hillstrom and Bill McNee, members of the Wisconsin Department of Natural Resources’ Forest Health team, made notable radio appearances during November.

Hillstrom, the DNR’s invasive forest pest coordinator, appeared on Wisconsin Public Radio to discuss the invasive pest hemlock woolly adelgid (HWA). The insect has not yet established a presence in Wisconsin.

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Go-To Online Resources For Urban Forestry

Posted on by janness

By Allen Pyle, UW-Extension Horticulture Outreach Specialist and Jay Dampier, DNR IRA Grant Coordinator, Jason.Dampier@wisconsin.gov or 920-765-1935

Reliable and up-to-date research-based information is vital for tree care professionals and urban foresters to make sound, scientific management decisions. To make trusted resources more accessible, UW-Extension’s Horticulture Program and Wisconsin DNR’s Urban Forestry Program have developed this curated selection of useful webpages with free information and resources for urban forestry professionals and community tree managers. Continue reading “Go-To Online Resources For Urban Forestry” →

Fourth Grade Arbor Day Seedling Orders Now Open

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The Wisconsin Department of Natural Resources (DNR) is offering free tree seedlings to every fourth-grade student in Wisconsin as part of its annual Arbor Day tree planting program.

Wisconsin fourth grade principals, teachers and homeschoolers can now place seedling orders and coordinate delivery by completing the 2026 Arbor Day application by March 16, 2026. Continue reading “Fourth Grade Arbor Day Seedling Orders Now Open” →

Beware Of Invasive Plants In Your Holiday Décor

Posted on by akabelowsky
The berries of round leaf bittersweet grow in clusters at each leaf axil and are beautiful, but this highly invasive plant makes it unsuitable for use in your fall decorations.

The berries of round leaf bittersweet (Celastrus orbiculatus) grow in clusters at each leaf axil and are beautiful, but this highly invasive plant makes it unsuitable for use in your fall decorations. / Photo Credit: Chris Evans, University of Illinois, Bugwood.org

By Wisconsin DNR

With the holiday season drawing near, it’s time for the Wisconsin Department of Natural Resources (DNR) to remind home crafters to be wary of using invasive plants in fall and winter decorations.

While holiday decorations made from natural materials can be beautiful, some wreaths and other home decorations may contain invasive species.

A quick Google or Pinterest search for décor ideas brings up a slew of orange-tinged images: pumpkins, leaves, pinecones and pretty fall foliage — sometimes boasting small, red-orange berries. While you can safely cloak your home in most of these items, avoid the one with the red-orange berries, as it likely comes from the non-native, woody vine called round leaf bittersweet (Celastrus orbiculatus, previously known as Oriental bittersweet).

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Take Advantage Of Mild Winter Days To Prune Trees

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An arborist uses climbing safety gear to prune an oak tree along a road.

An arborist uses climbing safety gear to prune an oak tree along a road. / Photo Credit: Wisconsin DNR

By Mike Hillstrom, Forest Invasive Pest Coordinator, Fitchburg
Michael.Hilstrom@wisconsin.gov or 608-513-7690

Winter is an ideal time to perform trimming, cutting and brush removal work on and near trees, especially oak trees.

Winter is the best time to prune because the insects and diseases that attack oak trees, such as oak wilt, are not active. Pruning and other work can be done around oak trees from after the first hard freeze in the fall until the high-risk period for oak wilt begins in April.

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Stumping Heterobasidion Root Disease With Cellu-Treat®

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Photo of a freshly cut tree stump after treatment with fungicide to prevent infection with Heterobasidion root disease. The fungicide is dyed blue to help ensure complete coverage.

A freshly cut tree stump after treatment with fungicide to prevent infection with Heterobasidion root disease. The fungicide is dyed blue to help ensure complete coverage. / Photo Credit: Wisconsin DNR

By Tim Shively, DNR Forest Health Specialist, Eau Claire
Timothy.Shively@wisconsin.gov or 608-772-6974

Treating freshly cut conifer stumps is critical to preventing infection by Heterobasidion species, causal agents of Heterobasidion root disease (HRD).

Within this genus, H. irregulare is believed to be the only species in Wisconsin, and it causes the mortality of overstory pine and spruce trees. The DNR has developed comprehensive guidelines to assist landowners, property managers, foresters, and loggers with determining whether stump treatments are necessary to prevent the introduction or spread of HRD at a given site.

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Did You Know? Facts About Pine Webworm

Posted on by akabelowsky

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

Webbing and a collection of frass (caterpillar excrement) around these cones is the web nest of pine webworm. / Photo Credit: Wisconsin DNR

Pine webworm (Pococera robustella) is a native moth whose caterpillars feed on pine needles. In Wisconsin, the caterpillars prefer young jack pine and red pine. A single generation per year occurs in Wisconsin.

Young larvae mine needles, feeding within the needle. Older larvae form a compact web that they fill with small, oval pieces of frass. In early fall, the larvae drop to the ground to pupate and spend the winter.

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