By Dan Buckler, DNR Urban Forest Assessment Specialist; Daniel.Buckler@wisconsin.gov or 608-445-4578
Autumn is a wonderful time for planting trees. And after the trees go in the ground, please take a few minutes to document the effort in the Wisconsin Tree Planting Map. The map was designed to help track trees planted to advance the state’s pledge to the Trillion Trees Initiative.
By Bill McNee, DNR Forest Health Specialist, Oshkosh;
Bill.McNee@wisconsin.gov or 920-360-0942
A tree shows high numbers of spongy moth caterpillars, though the majority of the caterpillars have been killed either by virus (hanging in an inverted V) or fungus (hanging in a stretched line, head down). The virus and fungus helped to quell a potential outbreak in many areas of the state in 2024. / Photo Credit: Bill McNee, Wisconsin DNR
As the 2023 spongy moth season ended, there were hopes for a return to colder and wetter conditions in 2024 so that the spongy moth outbreak would decline or even come to an end.
What wound up happening in Wisconsin was the “lost winter,” the warmest since recordkeeping began in 1895. Given this warmth, there were concerns that the widespread spongy moth outbreak would continue for a third consecutive summer, with good caterpillar survival, ongoing defoliation and high rates of tree mortality in already stressed forests.
By Art Kabelowsky, DNR Outreach and Communications, Fitchburg;
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
The main page of the TreeSnap app as seen on a mobile phone. / Photo Credit: TreeSnap.org
It takes more than a village to foster healthy forests. More than a township, a city and a county, too. Sometimes, even more than a state.
That’s why the Great Lakes Basin Forest Health Cooperative (GLB FHC) was formed four years ago by Holden Arboretum in Ohio and the U.S. Department of Agriculture Forest Service.
Geographically, the group’s region encompasses an area from New Jersey to Wisconsin. The Wisconsin Department of Natural Resources (DNR) is an active member.
Continue reading “Cooperative Enlists Public To Make Tree Health A Snap”
By Carmen Hardin, Director, DNR Applied Forestry Bureau, Rhinelander;
Carmen.Hardin@wisconsin.gov
A graphic shows changing tornado risk trends in the United States from 1980 to 2020. All Wisconsin counties are showing an increase in tornado days. / Map Credit: Inside Climate News, Stephen M. Strader et. al., Nature Magazine
We are often asked difficult questions about our forests, their health and how climate change is impacting them. Here is a curated collection of resources that may help you answer some of those questions. Continue reading “Forest Health and Climate Change Resources”
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.
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 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”
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
Oak leaves that drop from a tree infected with oak wilt may be all brown or all green, or often they will have green near the base of the leaf and the outer portions will be brown or watersoaked green. / Photo Credit: Linda Williams, Wisconsin DNR.
The middle of summer is the time to start watching oak trees for symptoms of oak wilt. Although symptoms show up suddenly and leaves drop quickly, symptoms can emerge anytime between now and when leaves turn color in the fall.
Trees that were wounded in the spring and became infected with the fungus that causes oak wilt will usually die that same year. In established oak wilt pockets, the fungus moves underground through grafted root systems and trees will wilt as the fungus moves into the tree.
