Cold temperatures across the state of Wisconsin on Jan. 25, 2026. / Graphic Credit: National Weather Service
By River Mathieu, DNR Forest Health Specialist, Fitchburg
River.Mathieu@wisconsin.gov or 608-772-2758
Wisconsin experienced a polar vortex in late January 2026, and temperatures got chilly throughout the state, even reaching close to -40⁰ F in some places! Although it has warmed up, the cold weather is still fresh in everyone’s minds, leaving insect and forest lovers alike wondering how insects survive temperatures that cold.
The Wisconsin Department of Natural Resources Forest Health staff has received several questions over the past month about how insects survive cold weather in winter and whether the January temperatures were cold enough to kill insect pests.
The purpose of the 
The cooperative agreement between the USDA Forest Service and the Davey Tree Expert Company, which typically funds the delivery of i-Tree, has been 
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The Urban and Community Forestry Society (UCFS) Industry Trends committee – charged with monitoring the issues impacting your work – is seeking information on your experiences with insurance companies and urban tree canopy. There is growing evidence that insurance companies are directing the pruning or removal of trees, and the committee wants to fully understand the issue. Your responses to the survey below will help compile stories and evidence so that UCFS can work with industry partners and draft position statements. 