Care for your woods

Increased Tree Mortality Seen As Spongy Moth Outbreak Ends

Posted on by akabelowsky
Mature spongy moth larva on a tree at Potawatomi State Park in Door County, July 2025.

Mature spongy moth larva on a tree at Potawatomi State Park in Door County, July 2025. / Photo Credit: Wisconsin DNR

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

Wisconsin’s recent period of high spongy moth populations (an “outbreak”) came to an end in 2025, as the remaining known hotspots were aerially sprayed or naturally collapsed. Only a handful of large larvae were observed or reported by property owners.

Spongy moth populations are likely to be low across the state for at least the next few years. However, it is possible that some sites may experience a population increase before then, if local weather conditions are favorable for the insect.

Continue reading “Increased Tree Mortality Seen As Spongy Moth Outbreak Ends” →

Report Invasive Hemlock Insects This Winter

Posted on by akabelowsky
Small, white hemlock woolly adelgid eggs found on the needles of a tree in Bastian, Virginia, in 2017.

Small, white hemlock woolly adelgid eggs are found on the needles of a tree in Bastian, Virginia, in 2017. / Photo Credit: Bill McNee, Wisconsin DNR

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

Hemlock woolly adelgid (HWA) looms as a major threat to Wisconsin’s hemlock trees. As the infestation of these invasive, aphid-like insects spreads in Michigan and other states in the eastern United States, Wisconsin is preparing to respond when it arrives.

HWA is most evident in winter and spring as fluffy, white, woolly balls that are present at the base of hemlock needles. These fluffy, waxy balls cover adult female adelgids and eggs.

Continue reading “Report Invasive Hemlock Insects This Winter” →

Take Advantage Of Mild Winter Days To Prune Trees

Posted on by akabelowsky
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.

Continue reading “Take Advantage Of Mild Winter Days To Prune Trees” →

Stumping Heterobasidion Root Disease With Cellu-Treat®

Posted on by akabelowsky
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.

Continue reading “Stumping Heterobasidion Root Disease With Cellu-Treat®” →

Tree City USA – Online Portal Open, No More Paper Applications!

Posted on by janness

By Laura Buntrock, DNR Urban Forestry Partnership & Policy Specialist, Laura.Buntrock@wisconsin.gov or 608-294-0253

kids holding a Tree City USA bannerThe online portal for Tree City USA (TCUSA) is now open, with applications due Dec. 31. If you’re new to TCUSA, you can learn more about the program on the Arbor Day Foundation’s (ADF) website or from your DNR Urban Forestry Coordinator. Please note that beginning this year, Arbor ADF is no longer accepting paper applications. You can create an account by clicking “sign up now” on the application portal login page. Within the online portal, you will have access to your historical data. More information is available on ADF’s FAQ page. Continue reading “Tree City USA – Online Portal Open, No More Paper Applications!” →

Don’t Stop Watering Your Trees Yet!

Posted on by janness

By Brian Wahl, DNR Urban Forestry Coordinator, Brian.Wahl@wisconsin.gov or 608-225-7943

A simple act, a science and an art, but bottom line – all trees need water (even in autumn)

It’s a very dry start to autumn this year. Heck, it’s been a dry second half of summer, but thanks to our lovely wet spring, we aren’t in a drought yet. However, areas of the state are “abnormally dry” according to the U.S. Drought Monitor. So be sure to get out there and water your newly planted trees! If you have the time, your established trees would appreciate a cool drink of H20 as well.

screenshot of WI drought map

Continue reading “Don’t Stop Watering Your Trees Yet!” →

Urban Wildlife Damage Abatement And Control Grants Now Open

Posted on by janness

white tail deerUrban Wildlife Damage Abatement and Control grants help urban areas develop wildlife plans, implement specific damage abatement and/or control measures for white-tailed deer and/or Canada geese. They are available to any town, city, village, county or tribal government with a population density of not less than 125 persons per square mile. This grant provides a 50% cost share up to $5,000 for eligible costs. The application deadline is Dec. 1.

Learn more on the DNR website.

DNR Tree And Shrub Seedling Sales To Begin Oct. 6

Posted on by janness

The Wisconsin Department of Natural Resources (DNR) is accepting seedling orders from Wisconsin landowners for trees and shrubs to be planted in spring 2026, starting Oct. 6, 2025.

Wisconsin forest nurseries have provided high-quality, native tree seedlings, appropriate for planting throughout Wisconsin, for over 100 years. Seedlings grown at the state nurseries are used for reforestation and conservation plantings on private, industrial, tribal and public lands. Continue reading “DNR Tree And Shrub Seedling Sales To Begin Oct. 6” →

Upcoming Trainings

Posted on by janness

a group of people outside facing an instructor*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 management and planning, urban tree diversity, root pruning, invasive species, urban wood, evergreen diseases, EHAP, the TRAQ program and fall foliage. Continue reading “Upcoming Trainings” →