Summary includes findings on insects, disease outbreaks and other impacts to Minnesota forests
The Minnesota Department of Natural Resources has released its 2024 Forest Health Annual Report, which uses data from aerial surveys and on-the-ground site visits to compile information about insect outbreaks, disease epidemics, and other impacts to the state’s forests.
DNR aerially surveyed 17.5 million acres of Minnesota for damage to forests in 2024. Since the early 1950s, aerial surveys have been a valuable tool for discovering, tracking, and managing forest health threats like spruce budworm, oak wilt, ice storm damage, eastern larch beetle, and more.
“By tracking changes and trends of what’s happening to trees, the DNR provides information that landowners and forest managers can use to help make our forests healthier and more resilient,” DNR Forest Health Program Coordinator Brian Schwingle said.
Key findings in the 2024 report include:
- The rainy growing season of 2024 helped reduce oak mortality from twolined chestnut borer and Armillaria root disease. However, the rain caused widespread fungal leaf disease on poplars across Minnesota, though affected trees should not be impacted long-term.
- Spruce budworm damaged more acres in 2024 than it has since 1961. This damage was concentrated in St. Louis, Lake, and Cook counties.
- Emerald ash borer was discovered in five additional counties, increasing the number of Minnesota counties with known EAB infestation to 53.
- Oak wilt was confirmed for the first time in Carlton and Kandiyohi counties, bringing the number of Minnesota counties with known oak wilt to 33.
Managing forests so they can thrive is a cooperative effort. Minnesotans can help keep trees and forests healthy through proper yard tree care and forest management.
To help reduce the spread of harmful pests and diseases, buy and burn local firewood and report EAB if spotted outside the quarantine area to the Minnesota Department of Agriculture.