The forest health chapter of Wisconsin’s 2020-2030 Statewide Forest Action Plan, completed in June 2020, highlights the impacts of insects, diseases, invasive plants and worms in Wisconsin’s forests.

Forest health experts from government agencies, universities and tribes worked together to evaluate these current impacts. They then developed goals and strategies to help the forestry community refine how it will invest state, federal and partner resources to address major forest health management and landscape priorities over the next ten years.

Forest health is a critical component of the plan because native and non-native pests increase tree mortality to a level that negatively affects forest stocking levels, clean water, wildlife habitat and raw material for wood products. This causes economic losses and undesirable management outcomes.

Invasive species can be particularly devastating to forests because:

• They reduce tree regeneration, making regrowing or establishing new forests more difficult.
• Major outbreaks may change the tree species composition on a site and its ability to withstand future stresses.
• Once established, they are very difficult to control and exterminate.

The current assessment of forest health in Wisconsin evaluates the impacts of several invasive species, including emerald ash borer, oak wilt, a variety of invasive plants and earthworm species. However, it’s difficult to predict what invasives will be the highest priority in five to ten years. Invasives like hemlock woolly adelgid are present in neighboring Michigan. Additionally, Asian longhorned beetle and spotted lanternfly could be introduced to Wisconsin at any time via infested firewood or other products shipped to the state.

External quarantines and outreach campaigns are designed to increase public awareness and reduce the likelihood of introduction. The Wisconsin Department of Natural Resources (DNR) and its partners actively monitor for new introductions and take action to eliminate non-native species. Actions include forest management paired with integrated pest management techniques like biological control. The public plays a major role in the detection of new invasive species through mobile application submissions and trained citizen scientists.