By Art Kabelowsky, DNR Outreach and Communications, Fitchburg;
Arthur.Kabelowsky@wisconsin.gov , 608-335-0167
The members of the Wisconsin Department of Natural Resources (DNR)’s Forest Health team are often asked by media to educate their listeners, readers and viewers about the forest health topics of the day.
Wisconsin Public Radio (WPR) is in frequent contact with Forest Health team members and makes its broadcasts and articles available to the public online.
A map of the current Cooperative Invasive Species Management Areas (CISMAs) in Wisconsin. / Map Credit: Wisconsin DNR
By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391
When it comes to fighting invasive plants, Wisconsin’s Cooperative Invasive Species Management Areas (CISMAs) are often the first line of defense (and offense).
These regional groups provide a localized resource for landowners looking for invasive plant education, identification support and assistance with controlling invasives on their properties.
With 13 CISMAs operating throughout Wisconsin, these groups accomplish a lot each year. CISMA efforts range from fieldwork outings and landowner education workshops to tool-share programs and day-long, control-based field trips.
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Two photos show maple branches that died recently due to previous damage from squirrels. / Photo Credit: Linda Williams, Wisconsin DNR
Have you noticed maple branches suddenly dying this summer?
Sudden mortality of maple branches during the summer in northern Wisconsin is often a result of squirrel damage that occurred in late winter and early spring.
In late winter and early spring, gray squirrels strip the bark of maples to get at the sweet maple sap. When the damage is extensive or severe, entire trees or branches will be killed immediately and will not leaf out in the spring.
Continue reading “Winter Squirrel Damage Killing Maple Branches”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
A closeup photo of Japanese beetles defoliating basswood leaves. The invasive pest is becoming more prevalent in northern Wisconsin. / Photo Credit: Linda Williams, Wisconsin DNR
The Japanese beetle (Popillia japonica) is an invasive insect that feeds on many plant species. The pests “skeletonize” leaves by eating the material between the veins.
Adult Japanese beetles feed on the flowers and leaves of more than 300 plant species, including trees, shrubs and herbaceous plants. Forest trees can be defoliated, with open-grown or edge trees suffering the highest defoliation rates.
When it comes to fighting invasive plants, Wisconsin’s Cooperative Invasive Species Management Areas (CISMAs) are often the first line of defense (and offense).
These regional groups provide a localized resource for landowners looking for invasive plant education, identification support and assistance with controlling invasives on their properties.
By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center
Erika.Segersonmueller@wisconsin.gov or 715-492-0391
The slightly off-center silvery midrib of Japanese stilt grass leaves provides a key to identification. / Photo Credit: Leslie J. Merhoff, University of Connecticut, Bugwood.org
Want an advantage over your taller friends? Try propping yourself up on a pair of stilts. As its name suggests, this is precisely how Japanese stilt grass operates. It uses “stilts” (branching rootlets near its base) both as support and to sprawl over nearby plants.
Japanese stilt grass (Microstegium vimineum) is an invasive, warm-season annual grass. It grows one to three feet tall and has an aggressive, mat-like growth that creates dense patches and discourages native plants from establishing. It is also a prolific seed producer, with each plant producing up to 1,000 seeds that can easily spread over land and water during its growing season.
Continue reading “Japanese Stilt Grass An Aggressive New Invasive”
By Paul Cigan, DNR Forest Health Specialist, Hayward
Paul.Cigan@wisconsin.gov or 715-416-4920
Aerial view of jack pine budworm defoliation in jack pine stands in Douglas County during the 2023 outbreak. / Photo Credit: Paul Cigan, Wisconsin DNR
Jack pine defoliation caused by the jack pine budworm (JPBW) continued at mostly light levels this year, affecting stands in the Central and Northwest Sands Ecological Regions of Wisconsin.
In the Northwest Sands, jack pine stands experienced light and scattered defoliation across Burnett, Douglas, Polk and Washburn counties. In the Central Sands, JPBW caused moderate to heavy defoliation across roughly 500 acres of jack pine on county and state forests in Jackson County, east of Black River Falls.
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Hemlock crowns remained thin this summer at a Vilas County plot that saw defoliation by spruce budworm in 2023. / Photo Credit: Linda Williams, Wisconsin DNR
Spruce budworm was observed defoliating a stand of hemlock trees in Vilas County in 2023. This stand was revisited in 2024 and although defoliation was only light this year, significant thinning in the tops of hemlocks was noted.
Hemlock is not a preferred host for spruce budworm, and the defoliation in 2023 was due to an extremely high population of spruce budworm in that area.
By Michael Hillstrom, Forest Health Specialist, Fitchburg
Michael.Hillstrom@wisconsin.gov
Oak decline at Big Foot Beach State Park caused by flooding, drought, spongy moth defoliation, twolined chestnut borer and Armillaria. / Photo Credit: Michael Hillstrom, Wisconsin DNR
Bur and white oaks, most of them more than 100 years old, have experienced rapid mortality (within one to two years) over the past four years in southern Wisconsin and neighboring states. Research into the cause is ongoing, but the evidence so far suggests it’s an oak decline.
Oak declines are not caused by a single issue, but rather by the stacking of multiple health issues. Drought, flooding, storm damage, age, twolined chestnut borer, Armillaria and other root pathogens, and spongy moth and oak leafroller defoliation all play a role in the damage.
Continue reading “Oak Decline Continues In Southern Wisconsin”
By Michael Hillstrom, Forest Health Specialist, Fitchburg
Michael.Hillstrom@wisconsin.gov
An adult bark beetle found infesting a white pine branch in 2024. / Photo Credit: Michael Hillstrom, Wisconsin DNR
Conifer mortality in southern Wisconsin has increased in 2024. Regardless of the conifer species, the common theme has been heavy infestation by bark beetles.
This increased bark beetle activity is likely linked to the 2023 drought, which lasted from May to September. Wisconsin experienced the fifth-driest May-July period on record and the fifth-driest meteorological summer (June-August) summer on record. The drought peaked during the middle of September before much-needed rain finally arrived.
Continue reading “Bark Beetles Infest Drought-Stressed Conifers”
