Northern WI Forest Health

Forest Tent Caterpillar Outlook Stays Low

Posted on by akabelowsky
A close-up photo showing forest tent caterpillar larvae displaying gregarious behavior and feeding on a tree leaf.

Forest tent caterpillar larvae displaying gregarious behavior and feeding on a tree leaf. / Photo Credit: Paul Cigan, Wisconsin DNR

By Paul Cigan, Wisconsin DNR Forest Health Specialist
Paul.Cigan@wisconsin.gov or 715-416-4920

Forest tent caterpillar (FTC) populations do not appear to be making a significant return this growing season.

Spring egg mass surveys indicate that populations continue to remain low, continuing the longest documented interphase between outbreaks on state record, at 22 years and counting. The interphase provides some relief for the health of aspen stands recovering from several consecutive years of recent spongy moth defoliation.

Continue reading “Forest Tent Caterpillar Outlook Stays Low” →

Red Pine And Hemlock Needles Suddenly Looking Brown

Posted on by akabelowsky
A photo showing hemlock needles affected by winter desiccation that have started browning at the needle tips and moving inward, sometimes killing the entire needle.

Hemlock needles affected by winter desiccation will start browning at the needle tips and move inward, sometimes killing the entire needle. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, DNR Forest Health Specialist
Linda.Williams@wisconsin.gov or 920-360-0665

During the winter months, warm or sunny weather can wreak havoc on evergreen trees.

Conifers such as hemlock, pines and fir can lose moisture from their needles during the winter. If too much moisture is lost, those needles can quickly turn yellow or brown once the weather warms up in the spring.

Extensive browning of needles on hemlock — sometimes more than 50 percent of the needles – was observed in scattered areas of Oneida and Bayfield counties by the second week of April. The brown needles eventually dropped from the trees, leaving the remaining foliage looking very thin. Buds on the trees appeared viable, and the trees should break bud as normal.

Continue reading “Red Pine And Hemlock Needles Suddenly Looking Brown” →

SilviCast Digs Into The Buckthorn Battle

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The logo for the Silvicast, a podcast hosted by Wisconsin DNR silviculturists Greg Edge and Brad Hutnik and produced by the University of Wisconsin-Stevens Point's Wisconsin Forestry Center.

The logo for the Silvicast, a podcast hosted by Wisconsin DNR silviculturists Greg Edge and Brad Hutnik and produced by the University of Wisconsin-Stevens Point’s Wisconsin Forestry Center. / Graphic Credit: UW-Stevens Point

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

They talked about pulling it, smothering it, using herbicide on it, making turkey calls and making curtain rods from it.

They even wondered if they should just “kill it with fire.”

But it seems Midwestern foresters’ never-ending battle against buckthorn requires a brainier approach.

Continue reading “SilviCast Digs Into The Buckthorn Battle” →

Web-Spinning Caterpillars Not Spongy Moth

Posted on by akabelowsky

By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov,  920-360-0665

You may already be seeing the web nests created by eastern tent caterpillars, which hatch early in the spring and start feeding on emerging leaves as the weather warms up.

Eastern tent caterpillars can sometimes be mistaken for forest tent caterpillars or spongy moths. Check out the DNR’s comparison fact sheet, which includes pictures for identification and control options. Continue reading “Web-Spinning Caterpillars Not Spongy Moth” →

Ice Storm Damage Found In Northeastern Forests

Posted on by akabelowsky
Photo of young red pine trees bent over and flattened by the weight of ice and snow. after an ice storm.

Young red pine trees bent over and flattened by the weight of ice and snow. They will not recover. / Photo Credit: Levi Koski

By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov, 920-360-0665
and Sam Blake, DNR Forester, Crandon
Samuel.Blake@wisconsin.gov, 715-216-6396

On Saturday, March 29, and continuing throughout the day on Sunday, March 30, northeastern Wisconsin experienced freezing rain, causing ice accumulations of one-quarter to one-half inch.

The freezing rain weighed down branches of trees. Then, to add to the weight of the ice on the trees, the freezing rain changed to wet, heavy snow with accumulations of up to 7 inches. The combination of ice and wet, heavy snow caused branches to break. In some cases, entire trees broke off.

Pine plantations seemed to be hardest hit, with the tops of some trees becoming so weighed down that trees leaned over and stems snapped. Continue reading “Ice Storm Damage Found In Northeastern Forests” →

Columbian Timber Beetle Fact Sheet Debuts

Posted on by akabelowsky
Photo showing staining, in the shape of a many-pointed star, evident in the cut ends of silver maple logs.

Staining, in the shape of a many-pointed star, is evident in the cut ends of silver maple logs. / Photo Credit: Chris Firgens, Oconto County Forest

By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665

Columbian timber beetle (Corthylus columbianus) is an ambrosia beetle native to the eastern United States.

In Wisconsin, we have had reports of Columbian Timber Beetle (CTB) attacking silver maple in the northeastern and lakeshore areas of the state, dating back to the early 1990s. The insects have caused significant staining from repeated attacks. In southern Wisconsin, CTB can attack oaks to a lesser degree, including bur, northern red and white oak.

Continue reading “Columbian Timber Beetle Fact Sheet Debuts” →

Fight The Bite! Watch For Ticks

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By Michael Hillstrom, DNR Forest Health Specialist
Michael.Hillstrom@wisconsin.gov

Ticks are active now, so it’s time to start taking precautions to prevent tick bites and transmission of the diseases they carry. Whenever temperatures at ground level get above 40-42 degrees Fahrenheit, ticks will start to be active.

Continue reading “Fight The Bite! Watch For Ticks” →

Watch For Oak Decline And Mortality This Summer

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Oak decline and mortality at Big Foot Beach State Park in 2024.

Oak decline and mortality at Big Foot Beach State Park in 2024. / Photo Credit: Wisconsin DNR

By Michael Hillstrom, DNR Forest Health Specialist
Michael.Hillstrom@wisconsin.gov

Oak decline and mortality continue to be an issue in Wisconsin, and because of the recent droughts and spongy moth outbreak, we expect these impacts to become more widespread this summer.

Forest decline is the progressive loss of tree and stand vigor and health over several years without obvious evidence of a single causal factor. Typically, trees die in a scattered fashion across a large area over several years. The additional stress from defoliation can result in pockets of heavy oak mortality, particularly on dry, sandy sites and steep, rocky ridges and hills.

Continue reading “Watch For Oak Decline And Mortality This Summer” →

Squirrels Can Damage Trees During Late Winter

Posted on by akabelowsky
Photo showing that squirrels have removed significant amounts of bark from a maple tree's trunk to get at the tasty cambium layer underneath.

Squirrels have removed significant amounts of bark from this maple to get at the tasty cambium layer underneath. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, DNR Forest Health Specialist
Linda.Williams@wisconsin.gov or 920-360-0665

Squirrels can be fun to feed and fun to watch, but when they start damaging or killing your trees, well, that’s not so cute.

It’s the time of year when we start to have some warm days that allow sap to start moving in trees. If there are broken branches or damaged bark, the tree can drip sap. And that can attract squirrels.

Continue reading “Squirrels Can Damage Trees During Late Winter” →

Squirrel Or Porcupine Damage: How Do You Know?

Posted on by akabelowsky
Photo showing squirrel tooth marks on a tree. Squirrel tooth marks are small and look like narrow scratches where the animals have removed the tree’s bark.

Squirrel tooth marks are small and look like narrow scratches where the animals have removed the tree’s bark. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, Forest Health Specialist

Linda.Williams@wisconsin.gov or 920-360-0665

If something chewed the bark off your tree, how would you go about determining the culprit?

Quite a few animals can damage bark on trees, from deer and bears to rabbits and mice. But the damage from squirrels and porcupines can look very similar, especially from a distance. So, how can you tell the difference?

Continue reading “Squirrel Or Porcupine Damage: How Do You Know?” →