The cooperative agreement between the USDA Forest Service and the Davey Tree Expert Company, which typically funds the delivery of i-Tree, has been indefinitely halted. Without this funding, maintenance for i-Tree will be impacted and the tools could eventually cease to function.
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When Is The Best Time To Prune Trees?
By Elton Rogers, DNR Urban Forestry Coordinator
Elton.Rogers@wisconsin.gov or 414-294-8675
To best answer the titular question, I like to start by flipping the question on its head: When is the worst time to prune trees?
To answer this reworded question, we first need to acknowledge that “pruning is wounding.” Anytime you cut off a living portion of a tree, you are doing two main things:
- Removing photosynthetic material.
- Creating a potential entry point for decay.
A New, Intuitive Way To Measure Species Diversity
By Dan Buckler, DNR Urban Forest Assessment Specialist
Daniel.Buckler@wisconsin.gov or 608-445-4578
Especially in the wake of emerald ash borer, urban foresters have stressed species diversity as an important goal in the management of local trees. Now there is a new, intuitive way of tracking species diversity by simply counting how many species it takes to make up half of your community’s trees.
This metric is called the top diversity index, or TD-50 index, and was proposed in a 2022 article in Urban Forestry and Urban Greening by Natalie Love and others. The index is deceptively simple — by counting the minimum number of species it takes to comprise 50% of your trees, you have an easy benchmark to improve upon to reduce your reliance on a few species. Continue reading “A New, Intuitive Way To Measure Species Diversity”
Forest Health Annual Report Hot Off The Presses
The cover of the 2025 Wisconsin Department of Natural Resources Forest Health Annual Report. / Graphic Credit: Wisconsin DNR
By Art Kabelowsky, DNR Outreach and Communications, Fitchburg
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
The Wisconsin Department of Natural Resources (DNR) has made its 2025 Forest Health Annual Report ready to view and download.
This year’s edition contains 55 pages of reporting on forest health issues throughout Wisconsin, detailing methods employed by the DNR and other agencies to control pests, diseases and invasive plants.
Continue reading “Forest Health Annual Report Hot Off The Presses”
Hemlock Borer Attacks Stressed Hemlock
A hemlock borer larva inside channels in a hemlock tree. / Photo Credit: Steven Katovich, Bugwood.org
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Woodpeckers are often the first to know that a hemlock tree is being attacked by hemlock borer.
Woodpeckers will flake off the outer layers of bark to get at the tasty hemlock borer larvae under the bark, leaving the tree with a reddish hue that, once you’ve seen it, is unmistakable. The woodpecker damage quickly makes it obvious that the tree was fully infested from top to bottom by hemlock borer.
Be Mindful Of Invasives During Holiday Clean-Up
A stack of discarded Christmas trees awaits processing at a drop-off facility. / Photo Credit: Wisconsin DNR
By Wisconsin DNR
Invasive plants and insects don’t mind playing the long game. After all, they’re just trying to survive and thrive, like the rest of us.
They’ll hang out as part of your holiday decorations throughout the season, just on the chance humans might dispose of them improperly, giving them an opportunity to find a new home in your yard or neighborhood.
Continue reading “Be Mindful Of Invasives During Holiday Clean-Up”
Community Spotlight: Rhinelander — How One Small Community Is Making Urban Forestry A Priority
By Tom Jerow, Rhinelander City Forester
View of the same street before and after urban forestry efforts.
The City of Rhinelander, like many communities with populations under 10,000, has struggled to maintain a vibrant urban forestry program. Funding and staffing are its main challenges. The city also faces a variety of urban forestry issues, including pests and diseases, species diversity, community engagement, catastrophic ice storms and aging sewer and water infrastructure. The latter is one of the most significant challenges. Continue reading “Community Spotlight: Rhinelander — How One Small Community Is Making Urban Forestry A Priority”
Repurpose Your Holiday Tree!
By Dan Buckler, DNR Urban Forest Assessment Specialist
Daniel.Buckler@wisconsin.gov or 608-445-4578
To say that working on a Christmas tree farm in high school led me into forestry would be a case of significant historical revisionism. Still, that experience swam in the same waters as reading Lord of the Rings, going on family vacations to the mountains, having a nearby municipal forest and other things that showed me that trees were the way.
Since then, I have increasingly appreciated holiday trees and other green things brought into households, not (just) in the harbinger-of-gifts way, but as reminders of life against a cold, seemingly bleak background. “Things will get better,” these green things announce. “Just wait!” Continue reading “Repurpose Your Holiday Tree!”
White Pine Blister Rust Can Devastate Young Stands
By Tim Shively, DNR Forest Health Specialist
Timothy.Shively@wisconsin.gov or 608-772-6974
A white pine blister rust canker as seen on a young white pine tree. / Photo Credit: Wisconsin DNR
Eastern white pine (Pinus strobus) has historically held great ecological, cultural and economic value throughout Wisconsin, a tradition which continues today. For more than 100 years, however, it has been threatened by a non-native, invasive fungal pathogen called Cronartium ribicola, or white pine blister rust (WPBR).
Continue reading “White Pine Blister Rust Can Devastate Young Stands”
Impacts Of Winter Weather On Trees
By Michael Hillstrom, DNR Forest Health Specialist
Michael.Hillstrom@wisconsin.gov
A stand of pines shows heavy damage from an ice storm in April 2025. / Photo Credit: Wisconsin DNR
Winter damage can significantly impact the health of trees. Keeping trees healthy through the fall is important for reducing winter stress. Provide water as needed to trees until the leaves start falling (for deciduous trees) or until the ground starts freezing (for conifers).