Best Management Practices

Oak Wilt Information Updated

Posted on by akabelowsky
University of Wisconsin-Madison Extension online tool to help with oak wilt decisions.

A University of Wisconsin-Madison Extension online tool provides users localized information about the estimated emergence status of the two most important insects that transmit oak wilt in Wisconsin. / Graphic Credit: University of Wisconsin-Madison Extension

By Kyoko Scanlon, DNR Forest Pathologist, Fitchburg
Kyoko.Scanlon@wisconsin.gov

In 2025, oak wilt was detected for the first time in Hughes Township, Bayfield County, a northern Wisconsin location where oak wilt remains uncommon. There were no new county finds in 2025.

Based on the findings in 2025, the maps in the Oak Harvesting Guidelines To Reduce The Risk Of Introduction And Spread Of Oak Wilt (the oak wilt guidelines), oak wilt fact sheet and were updated. The maps in the oak wilt guidelines are good through the end of 2026.

Continue reading “Oak Wilt Information Updated” →

Oak Wilt High Risk Period Quickly Approaches

Posted on by akabelowsky
A closeup of a fungal pressure pad under the bark of an oak tree infected with oak wilt.

A fungal pressure pad formed on the outside of the sapwood underneath the bark of an infected tree. The pad will create cracks in the bark, where beetles can enter and visit the pad and become covered in spores. They will then leave and move on to infect new trees through open wounds. / Photo Credit: Wisconsin DNR

By Alex Hornung, DNR Forest Health Specialist, Plover
Alexandra.Hornung@wisconsin.gov or 715-340-3810

It is again that time of year to pause operating in oak stands or pruning oak trees during the high-risk period for oak wilt, which begins in April. The high-risk period begins April 1 in the South, April 15 in the North, and ends in both zones on July 15.

The high-risk period is determined by when the beetles that carry the fungus that causes oak wilt have emerged for the year and when they are carrying the highest number of fungal spores. When wounds are created by logging operations or other activities that expose sapwood, the beetles carry the fungus to the wounded tree, and the disease process begins.

Continue reading “Oak Wilt High Risk Period Quickly Approaches” →

Upcoming Training

Posted on by janness

group of people listening to a speaker in the woods* These training opportunities are provided as an information service only and do not constitute an endorsement from the Wisconsin Department of Natural Resources (DNR).

See below for information on training topics and events, including shade trees, fruit trees, chainsaw certification, tree diseases and pests, pruning and public perspectives on trees. Continue reading “Upcoming Training” →

Now Is Time To Seek Out Spongy Moth Egg Masses

Posted on by akabelowsky
Large spongy moth egg masses on a tree main stem.

Large egg masses are seen on a tree at the Kettle Moraine State Forest-Southern Unit in 2021. / Photo Credit: Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist, Oshkosh
Bill.McNee@wisconsin.gov

It certainly has been chilly in recent weeks, but spring is coming. When the weather warms up, the annual return of spongy moth caterpillars will begin.

The overall spongy moth population is currently low in Wisconsin. However, egg mass numbers may remain high enough to cause nuisance problems and heavy tree defoliation on individual trees or in small areas.

There’s a way for property owners to help keep the population down: Get out now to locate and properly dispose of spongy moth egg masses, which were produced by adult moths last summer. Each spongy moth egg mass contains hundreds of eggs that will hatch into hungry, leaf-eating caterpillars in the spring.

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When Is The Best Time To Prune Trees?

Posted on by janness

By Elton Rogers, DNR Urban Forestry Coordinator
Elton.Rogers@wisconsin.gov or 414-294-8675

To best answer the titular question, I like to start by flipping the question on its head: When is the worst time to prune trees?

To answer this reworded question, we first need to acknowledge that “pruning is wounding.” Anytime you cut off a living portion of a tree, you are doing two main things:

  • Removing photosynthetic material.
  • Creating a potential entry point for decay.

Continue reading “When Is The Best Time To Prune Trees?” →

Upcoming Trainings

Posted on by janness

* These training opportunities are provided as an information service only and do not constitute an endorsement from the Wisconsin Department of Natural Resources (DNR).

See below for information on training topics and events, including tree diseases and treatments, pest management, landscaping, career advancement, invasive species, pruning, volunteer management, new research, partnerships and developing an urban forest management plan. Continue reading “Upcoming Trainings” →

Repurpose Your Holiday Tree!

Posted on by janness

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

To say that working on a Christmas tree farm in high school led me into forestry would be a case of significant historical revisionism. Still, that experience swam in the same waters as reading Lord of the Rings, going on family vacations to the mountains, having a nearby municipal forest and other things that showed me that trees were the way.

Since then, I have increasingly appreciated holiday trees and other green things brought into households, not (just) in the harbinger-of-gifts way, but as reminders of life against a cold, seemingly bleak background. “Things will get better,” these green things announce. “Just wait!” Continue reading “Repurpose Your Holiday Tree!” →

Upcoming Trainings

Posted on by janness

*These training opportunities are provided as an information service only and do not constitute an endorsement from the Wisconsin Department of Natural Resources (DNR).

See below for information on training topics and events, including ISA certification exam preparation, plant propagation, winter tree identification, urban forest restoration, research trends and electrical hazards. Continue reading “Upcoming Trainings” →

Arbor Day Seedling Orders Open To Fourth-graders

Posted on by akabelowsky

By Wisconsin DNR

A worker plants a red pine seedling provided by the Wisconsin Department of Natural Resources.

A worker plants a red pine seedling provided by the Wisconsin Department of Natural Resources. / Photo Credit: Wisconsin DNR

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.

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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” →