5 Year Oak Wilt Containment Study (WI DNR)

Abstract

This is an ongoing study that began in 2015 and is expected to wrap up in 2020. There are two major goals of this study; (1) evaluate the effectiveness of girdle-herbicide control of below ground spread of oak wilt disease centers in field applications, and (2) develop operational guidance for the use of girdle herbicide methods of oak wilt control. The initial study objectives were to include 60 oak wilt pockets, with 50 treatments and 10 controls (five of each type – observation only, or girdle only) in the first two years of the project. In these first two years, we have collected data in 55 pockets (45 treatments and 10 controls), and have monitored 24 treatments and 5 controls from 2015. Several sites were selected throughout Wisconsin, including some private land sites. Sites were selected in 8 Wisconsin counties. Sites were chosen based on the stand qualities listed below as well as having relatively sandy soil and flat topography. By following these site restrictions, the study intends to show whether the girdle-herbicide method is still effective, even when conditions are extremely conducive to below ground transfer. The Silviculture Objective is to stop the below-ground spread of an active oak wilt pocket in order to maintain oaks into the future and test a novel approach to oak wilt control in forested settings where traditional treatments are impractical or cost-prohibitive.