Minnesota Forest Health 2024 Annual Report

Our Forest Health Annual Report summarizes statewide assessments on insects and diseases that cause trouble or concern in the woods, as well as impacts from events like drought and windstorms. Watching trends and monitoring outbreaks allows public land managers and private woodland owners to keep forests healthy by adjusting management approaches and preparing for future challenges.

So, what are some highlights from 2024?

The good

Overall, the return of above-average precipitation during the growing season benefitted many of Minnesota's forests. For example, indicators of oak decline slowed in 2024, with abundant rains contributing to a nearly 70 percent drop in mapped twolined chestnut borer damage.

The bad

Spruce budworm is a major problem in the northeastern part of the state.

This year, this native caterpillar damaged more acres than it has since 1961. Since 2021, spruce budworm has impacted over 2,000 square miles (1,330,000 acres), over 90 percent of which is in St. Louis, Lake, and Cook counties.

A wide variety of landowners and managers are working on this issue, but it continues to be a big challenge.

The ugly

While the rain was generally beneficial, it did promote fungal leaf diseases on deciduous trees and shrubs across the state. Particularly impacted were poplars, which displayed foliage marred with black or brown splotches, with many mostly defoliated before autumn. The good news is that these diseases look much worse than they are, and trees should leaf out fine this spring.

Delve into these findings and many more in the 2024 Forest Health Annual Report.

Did you know?

Each year, the DNR aerially surveys most of Minnesota’s forests, tracking outbreaks of forest insect and disease damage. Want to see trends over time? Past annual reports (1969-present) are available online.