Research

Tree Species In An Uncertain Future Climate

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

One of the many challenges for urban foresters in navigating climate change is the fact that while temperatures are elevated across every season, it can still get pretty cold in Wisconsin, even along Lake Michigan. Nonetheless, hardiness zones are shifting, and there is plentiful experimentation underway by Wisconsinites to identify which tree species are appropriate for their location throughout the 21st century.

The Northern Institute of Applied Climate Science produced species vulnerability lists for six locations in Wisconsin, projecting what species are likely at increased risk (i.e. more vulnerable) under different climate change scenarios. Those are great resources that use the same background methodology as a species vulnerability analysis done for the Milwaukee metropolitan area. Continue reading “Tree Species In An Uncertain Future Climate”

Forest Health Team Debuts Two New Fact Sheets

An image of the front page of a DNR fact sheet.

The front page of the Wisconsin DNR’s new Forest Health Fact Sheet on oak decline. / Graphic Credit: Wisconsin DNR

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

The Wisconsin Department of Natural Resources Forest Health team has published two new fact sheets, bringing the total count of its fact sheet offerings to 26.

The new fact sheets:

  • Fall Webworm: DNR Publication FR-622u discusses basic information on the biology of the insect (Hyphantria cunea), its life cycle, potential lookalike caterpillars and management options.
  • Oak Decline: DNR Publication FR-622v covers the tricky topic of oak decline, which is not caused by one distinct forest pest or problem but instead is the result of multiple factors — some predisposing, some inciting and some contributing — that work in combination to cause decline.

The fact sheets are designed in full color, with photos, and are meant to be printed out for reference or to carry into the field. They can also be viewed online. They can be printed on standard letter-sized paper. Most fact sheets are two pages, meant for two-sided printing; a few are four-page documents.

A complete directory of links to all DNR Forest Health fact sheets is available online.

University of Minnesota Seeks Reports On Dying Black Locust Stands

Wide view of struggling black locust trees.

A stand of dead or dying black locust trees. / Photo Credit: Norbert Frank, Bugwood.org

By Ryan Franke, University of Minnesota

The Blanchette Forest Pathology Lab at the University of Minnesota is leading a project to study black locust in Minnesota and Wisconsin and requests the help of foresters and the public in locating stands of dying black locust (Robinio pseudoacacia) this summer.

The university plans to collect native pathogenic fungi from stands of dying black locust and testing them for their suitability to biologically control black locust clones.

Continue reading “University of Minnesota Seeks Reports On Dying Black Locust Stands”

May Is Mental Health Awareness Month, But Trees Provide Benefits All Year Long

people doing yoga in a parkOver the years, a growing body of research has proven that regular access to trees makes us happier and healthier. They restore our sense of calm from head to toe — improving memory and attention span, enhancing cognitive functioning, lowering blood pressure and reducing cortisol levels. Continue reading “May Is Mental Health Awareness Month, But Trees Provide Benefits All Year Long”

Upcoming Training & Events

group of people learning to plant a tree* These training opportunities are provided as an information service only and do not constitute endorsement by the Wisconsin Department of Natural Resources (DNR).

See below for information on training topics and events including i-Tree, American elm research, oak health issues, invasives and private equity. Continue reading “Upcoming Training & Events”

Controlling Buckthorn With Plants

By Olivia Witthun, DNR Urban Forestry Coordinator, Olivia.Witthun@wisconsin.gov or 414-750-8744 and Elton Rogers, DNR Urban Forestry Coordinator, Elton.Rogers@wisconsin.gov or 414-294-8675

buckthorn The Cover It Up project is a suite of related research projects conducted by multiple partners in Minnesota that are evaluating the ecology and management of buckthorn and other invasive plant species. Buckthorn is an invasive understory plant that was introduced to Wisconsin well over 100 years ago. It was used primarily in hedgerows, prized for its lack of pest issues and the fact it greens up early and holds its leaves well into the fall. These once desirable characteristics are also what turned this non-native into one of our state’s worst invasive species, easily outcompeting our natives, taking over Wisconsin’s forests, riparian woods, savannas, prairies, old fields, roadsides and vacant lots. Continue reading “Controlling Buckthorn With Plants”

Community Spotlight: Tree Canopy Cover On Milwaukee School Properties

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

The thought of increasing a community’s tree canopy cover is sometimes overwhelming given how many landowners are present. Think about all the stakeholders who have to buy into the initiative, not only with enthusiasm, but likely contributing money and time as well.

Contrast that with a more actionable approach focused on areas where there’s a single landowner or manager.

This was the route taken by graduate student Michelle Hess in a recent paper for a UW-Milwaukee Geography course. Michelle investigated tree canopy on Milwaukee Public Schools (MPS) properties to identify which schools should be prioritized for future greening initiatives, like those organized through ReFlo. The goal was to use canopy data provided by the DNR, identify which schools had lower canopy cover, merge those data with median household income of the local Census tract and come up with a prioritized list of schools in need of tree planting. Continue reading “Community Spotlight: Tree Canopy Cover On Milwaukee School Properties”

Register For Tour Des Trees 2026

Tour des Trees 2026The Tour des Trees is a multi-day bike ride that not only raises funds for TREE Fund but also hosts multiple outreach events throughout the week, getting people together to learn more about the importance of tree research, proper tree care and why the industry is so vital to maintaining our urban forests.

Ride dates are Sept.12-18, 2026, riding from Greenville, South Carolina, to Asheville, North Carolina. Can’t ride all five days? Ride one to four days as your schedule allows.

See information on this year’s ride and register today on the TREE Fund website.

The 2026 Tour des Trees will be an epic ride that you won’t soon forget, so make this the year that you sign up and ride with us to support tree research. Continue reading “Register For Tour Des Trees 2026”

Wisconsin Sees First Recovery Of EAB Parasitoid Oobius Agrili

A plastic pan trap for wasps is hung from a tree branch.

A yellow pan trap used for trapping Oobius agrili wasps. / Photo Credit: United States Department of Agriculture Animal and Plant Health Inspection Service

By River Mathieu, DNR Forest Health Specialist
River.Mathieu@wisconsin.gov or 608-772-2758

One small adult wasp collected by United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) staff at Riedel Redmond Nature Preserve in Mosinee (Marathon County) was recently identified as Oobius agrili.

USDA APHIS staff collected several wasp specimens in yellow pan traps and sent them to a U.S. Forest Service expert for identification. This marks the first recovery of O. agrili in Wisconsin.

Oobius agrili is an emerald ash borer (EAB) parasitoid that was first released in Wisconsin in 2011 and has been released annually since then. O. agrili parasitizes EAB eggs on the bark of ash trees, consuming the EAB larvae inside the egg. Continue reading “Wisconsin Sees First Recovery Of EAB Parasitoid Oobius Agrili”

Forest Health Annual Report Hot Off The Presses

The cover of the 2025 Wisconsin Department of Natural Resources Forest Health Annual Report.

The cover of the 2025 Wisconsin Department of Natural Resources Forest Health Annual Report. / Graphic Credit: Wisconsin DNR

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

The Wisconsin Department of Natural Resources (DNR) has made its 2025 Forest Health Annual Report ready to view and download.

This year’s edition contains 55 pages of reporting on forest health issues throughout Wisconsin, detailing methods employed by the DNR and other agencies to control pests, diseases and invasive plants.

Continue reading “Forest Health Annual Report Hot Off The Presses”