By Jaqi Christopher, DNR Forest Invasive Plant Specialist, Rhinelander, Jacquelyn.christopher@wisconsin.gov
Giant hogweed is a large invasive species commonly confused with the native look-alike cow parsnip. Although giant hogweed is uncommon in Wisconsin, it’s important to know the difference between the two.
Giant hogweed can invade woodlots and get 8-20 feet tall. Photo Credit: Ramona Shackleford
By Bill McNee, DNR Forest Health Specialist, Oshkosh, bill.mcnee@wisconsin.gov or 920-360-0942
Early photo of EAB adults taken in June 2002, prior to the insect species being identified. Photo: USDA Animal and Plant Health Inspection Service
The beginning of July marked 20 years since we received news of an unidentified beetle that turned out to be the emerald ash borer (EAB), one of North America’s greatest tree killers. On July 1, 2002, DNR forest health staff received an email from USDA Animal and Plant Health Inspection Service about this beetle being associated with declining ash in southeast Michigan:
This is to notify you that in the past few days we have responded to a report of an insect pest feeding on ash in the western suburbs of Detroit. This follows what has been a series of reports of declining ash in this area over the past couple of years. However, in the past we have not been able to associate it with any particular insect or disease. We are now seeing a boring insect emerging from the infested trees in various sites… The adult, which is emerging now, resembles the shape and size of two lined chestnut borer. It is emerald, metallic green in color and leaves a D-shaped exit hole, similar to bronze birch borer… Continue reading “20 Year Anniversary Of Emerald Ash Borer Confirmation In North America”
By Paul Cigan, DNR Forest Health Specialist, Hayward, Paul.Cigan@wisconsin.gov or 715-416-4920; Mike Hillstrom, DNR Forest Health Specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov or 608-513-7690; and Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Oak leafrollers feed on leaves and roll/fold them with strands of silk. Photo: Wisconsin DNR
An outbreak of oak leafroller moth, Archips semiferanus, has been observed in many parts of Wisconsin this year. Oak leafrollers are native, early-season defoliators. This year they have consumed and rolled up oak leaves, giving the tree crowns a thin, yellow appearance. Continue reading “Leafroller Charged With Severe Oak Defoliation”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov, 920-360-0665
Have you ever seen an oak wilt fruiting body? Oak wilt is a fungal disease that kills trees in the red oak group (northern red oak, northern pin oak, black oak and other oaks with points on their leaves). Trees in the white oak group (white oak, burr oak, swamp white oak and other oaks with rounded leaves) are more resistant to the disease, but branches or branch tips can still be killed.
Oak wilt pressure pads can create a crack in the bark, allowing beetles to get into the spores. Photo: Wisconsin DNR
Continue reading “On The Lookout For Oak Wilt Fruiting Bodies”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665.
As you begin your summer travel, you may notice that many white pine trees along northern Wisconsin roadways have a lot of brown needles on them. Although it may seem concerning, most of these trees are sending out new needles as we speak.
Different conifer species can be impacted differently by salt spray. The white pine in the middle also shows lower branches that are green because they were protected by snow. Photo: Wisconsin DNR.
Continue reading “I Spy… Browning White Pine Stands Along Roads”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665.
Maples
Have you noticed any maple trees that appear brown or reddish and have fewer leaves than usual? The seeds, not the leaves, make the tan/red color. Those seeds are so plentiful this year that they can easily be spotted from a distance.
Maples with heavy seed crops may appear tan or reddish due to the color of the seeds and having very few green leaves in the canopy. Photo: Wisconsin DNR.
Continue reading “Slow Oaks And Maples With Too Many Seeds And Not Enough Leaves”
By Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665 & Paul Cigan, DNR Forest Health Specialist, Hayward, Paul.Cigan@wisconsin.gov, 715-416-4920.
Spring cleanup is always a busy time in the Northwoods as those with second homes and cabins make the trek northward to prepare for a summer of fun. For many, this will mean cleaning up trees and branches damaged by winter storms.
Large white pines (pictured here) and young birch growing on forest edges were most heavily impacted by winter’s storms. Photo: Wisconsin DNR
Continue reading “Spring Cleaning: Storm Damage Cleanup Brings Oak Wilt Risk”
By Brenna DeNamur, DNR Forest Health Outreach Specialist, Madison, Brenna.DeNamur@wisconsin.gov; Jaqi Christopher, DNR Forest Invasive Plant Specialist, Rhinelander, Jacquelyn.Christopher@wisconsin.gov; & Mary Bartkowiak, DNR Forest Invasive Plant Coordinator, Rhinelander, Mary.Bartkowiak@wisconsin.gov
Spring is here! Invasive plants, like garlic mustard, are often among the first green life to emerge in the new season.
Garlic mustard is an invasive plant that appears early in spring. Photo: Wisconsin DNR
Contact: Paul Cigan, DNR Forest Health Specialist
Paul.Cigan@wisconsin.gov or 715-416-4920
As April brings a high risk of the often-fatal oak wilt disease, the Wisconsin Department of Natural Resources (DNR) recommends not pruning or cutting oaks from April through July.
Do not prune, cut or wound oaks April through July.
Photo: Linda Williams
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Narrow grooves are left when squirrels chew the bark off a young tree or a branch.
Photo: Wisconsin DNR
In late winter, it’s common to see tree branches that have been freshly stripped of their bark. Damage can be extensive where entire branches, and sometimes entire small trees, can be stripped of bark. This damage, believe it or not, is from squirrels! While primarily found on sugar maples, you can also find squirrel damage on red maples and the occasional oak. So far this year, the damage has been noted in Langlade, Shawano, Oneida and Vilas Counties.
On sunny days, the pale wood of branches where the bark has been stripped off stands out in the forest. This type of feeding can remove enough bark to girdle the branches or the main stem, causing the tree to die from that point to the end of the branch. Branches that are not entirely girdled will continue to grow, and callus tissue will begin to grow over the wounds. If branches are nearly girdled, they may leaf out in the spring only to have the leaves suddenly wilt and die as hot weather hits because the tree can’t move enough water to keep the leaves alive. Continue reading “Squirrel Damage Mayhem”
