The OSU Research Forests will be conducting roadside herbicide applications across the McDonald, Dunn, and Cameron Forests. This work includes treatment along all roads, roadside ditches, and cut-banks.

To ensure public safety, the forests will be closed to the public beginning as early as June 22–26, 2026. Closure dates may shift depending on contractor availability and weather conditions.

As work locations vary throughout the closure, we will reopen completed segments of the forest to the public as soon as it is safe to do so.

Advance notice signs will be posted at each forest gate prior to application. On the day of treatment, signage will be updated to include the herbicide and application date.

The application operation will include a pilot vehicle, a spray truck, and a chase vehicle. Roadside spraying typically occurs every one to two years to help control invasive weeds and maintain the integrity of roadways and drainage systems.

If you have general questions about the roadside spraying program, please contact the OSU Research Forests office. For questions regarding specific herbicides, please contact the National Pesticide Information Center at 1-800-858-7378 or via our contact us page.