The Minnesota Department of Natural Resources has released its 2023 Forest Health Annual Report(files.dnr.state.mn.us/assistance/backyard/treecare/forest_health/2023-minnesota-forest-health-highlights.pdf), which summarizes findings about the pests, diseases, and other issues impacting the state’s forests. This data was collected through aerial surveys of 17.3 million acres in 2023 covering every forested area across the state, as well as on-the-ground site visits.
“Tracking trends and monitoring pest and disease outbreaks are important ways to support forest health,” Forest Health Program Coordinator Brian Schwingle said. “This information helps public land managers and private woodland owners understand overall forest conditions and manage forests to keep them healthy and resilient in the face of current and future challenges.”
Among the key findings in the report:
Spruce budworm damage was identified on around 664,800 acres of fir and spruce forests, the highest number of acres the native caterpillar has impacted in one year since 1961.
Damage from the eastern larch beetle surpassed a cumulative 1 million acres of tamarack this year since the current outbreak began in 2001. Longer growing seasons have allowed these beetles to reproduce more, leading to an increase in beetle populations in tamarack stands. Fortunately, recent research from the DNR and the University of Minnesota showed that some forests are recovering naturally over time.
Emerald ash borer was officially confirmed for the first time in Benton, Faribault, Lyon, McLeod, Mille Lacs, Morrison, Cass, and Clay counties, bringing Minnesota to a total of 46 out of 87 counties under quarantine. The DNR is engaged in a wide range of activities related to managing and reducing the impact of EAB.
The most widespread tree health problem was declining oaks, primarily caused by a combination of older age, consecutive years of significant drought, and two opportunistic pests (Armillaria root disease and two-lined chestnut borer) which are only serious problems for stressed oaks.
Minnesotans can help keep trees and forests healthy through proper yard tree care (mndnr.gov/treecare/caring-pruning.html) and forest management (mndnr.gov/foreststewardship).
Among adopting other best practices, homeowners should consider watering one or two of their favorite yard trees during significant drought, in compliance with local water use restrictions. People should buy and burn local firewood(mda.state.mn.us/plants-insects/firewood-information) and report EAB if spotted outside the quarantine area(mnag.maps.arcgis.com/apps/webappviewer/index.html?id=63ebb977e2924d27b9ef0787ecedf6e9) to the Minnesota Department of Agriculture (mda.state.mn.us/plants/insects).
