You may have participated in this survey led by DNR Urban Forestry Coordinator Don Kissinger in 2020 (if so, thank you!) Wisconsin municipalities with more than 2,500 residents were asked a series of questions about the types of trees they prefer to plant (such as root stock type and caliper size), which lesser-used species they had successfully planted, which species they cannot find but would like to plant, and whether they use a gravel bed.Continue reading “New DNR Publication: Results of the 2020 Diverse Urban Species Survey” →
Wisconsin DNR urban forest assessment specialist Dan Buckler had been monitoring weather forecasts for a month, waiting for just the right blisteringly hot day to launch a much-anticipated Milwaukee heat island mapping project. He’d been laser-focused on getting the one-day blitz in the books, and July 21 turned out to be go time.
The urban heat island effect explains the phenomenon that densely developed urban spaces are warmer than outlying places due to man-made surfaces (such as asphalt) absorbing and reradiating heat through the day and night. Trees are one method of reducing urban temperatures by providing shade and by putting more water vapor into the air via evapotranspiration.
Forest owners and land managers should be on the lookout for beech leaf disease (BLD), a destructive disease of beech trees. The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species like European, Oriental and Chinese beech (F. sylvatica, F. orientalis and F. engleriana).
Symptomatic striping seen from under the canopy. This photo was taken in Ohio. Photo: Wisconsin DNR
Conifer and hardwood trees have begun showing more apparent and often substantial signs and symptoms of damage from a severe hailstorm that spread across several northwestern Wisconsin counties on May 9, 2022.
The storm produced golf ball-size hailstones and high-speed winds causing catastrophic injury to tree branches and stems, in addition to defoliation. Few tree species were spared in its path. The heaviest impact occurred in northeastern Polk County, where defoliation of aspen and black locust reached nearly 100%, and pine exceeded 90% (Fig. 1). Red and white oaks show more moderate damage.
Figure 1. Polk County had nearly 100% defoliation from a severe May hailstorm. Photo: Wisconsin DNR
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
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” →
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” →