Forest Health_Content Page_Annual Reports

Forest Health Annual Reports

The DNR forest health team works to prevent, detect and control Wisconsin's forest pests, particularly invasive plants, insects and diseases that jeopardize trees and ecosystems. Through research, forest management guidance and education and outreach efforts, forest stability and sustainability is established and enriched.

Each year, staff create an annual report to give updates on the program and forest health threats in Wisconsin. Browse the newest reports below.

2024 Annual Report

Read about all of the latest forest health issues in Wisconsin, including:

  • Natural enemies of spongy moth (a virus and a fungus) saw an uptick in numbers that helped to reduce statewide defoliation levels in comparison to 2023.
  • With the discovery of emerald ash borer in Burnett County, the ash-killing pest has now established a confirmed presence in all 72 Wisconsin counties.
  • Storm damage during the high-risk period for oak wilt infection resulted in many new infections in 2024. The disease is known to be present in 66 counties.
  • The detection of elm zigzag sawfly in Portage County in July was the first in Wisconsin. However, it was quickly followed by discoveries in 20 other counties.

Read the Report

Annual report cover

Past annual reports

To access archived regional and annual reports dating back to 1951, contact your regional forest health specialist.