
Oak trees with thin canopies experiencing decline following spongy moth defoliation and drought in the prior few years. / Photo Credit: Wisconsin DNR
By River Mathieu, DNR Forest Health Specialist, Fitchburg
River.Mathieu@wisconsin.gov
Oak decline is a complicated forest health issue impacting oak forests in Wisconsin.
In the past few years, oak decline has been recorded in several regions of Wisconsin, primarily linked to spongy moth defoliation and drought conditions that occurred from 2022-2024.
As the summer months of 2026 continue to unfold, oak decline may continue in areas previously impacted by spongy moth and drought.




Beginning July 1, 2026, cities, villages, towns, counties, tribes and 501(c)(3) nonprofit organizations conducting projects in Wisconsin can apply for a regular or startup 2027 Wisconsin Department of Natural Resources (DNR) Urban Forestry grant. 

See below for information on training topics and events, including the WAA Summer Conference, leadership, pollinator habitats, safety, tree ID and the ISA Annual Conference.