Tree Climbers use new Research to Slow Oak Wilt Disease in Superior National Forest
Sep 06, 2023 09:04AM ● By Editor
From Superior National Forest - September 5, 2023
Forest Service tree climbers are a select group. Within the 20 states and the District of Columbia that makes up the Eastern Region of the USDA Forest Service, around 100 of these trained specialists work on various forest health and management projects.
The Superior National Forest currently has 12 trained tree climbers, including Paul Valento– Superior’s Silviculture Timber Stand Improvement and Region 9 Tree Climbing Coordinator, who has been ‘climbing’ since 2008 and is part of the National Technical Advisory Group for USDA Forest Service tree climbers. Tasked with a new project in 2022, these tree climbers came together from Minnesota’s Superior National Forest, Michigan’s Huron-Manistee National Forest, and Wisconsin’s Oconto River Seed Orchard to assist with testing a new technique for forest health against oak wilt disease, one of the deadliest diseases to red oaks in the Eastern U.S.
The technique to slow the spread of oak wilt disease was developed by foresters from Menominee Tribal Enterprises but has never been studied in a systematic way. To that end, a unique, collaborated group with staff from the Minnesota, Wisconsin, and Michigan Department of Natural Resources; USDA Forest Service State, Private, & Tribal Forestry Program; Michigan State University; and the University of Minnesota took on the task of researching the technique.
James Jacobs–Forest Health Group Leader for USDA Forest Service Forest Health Protection described the group’s commitment to the project, “partnerships are the key to getting work accomplished. It was really nice to see the collaboration between the tree climbers from the national forests in the Eastern Region and our state forest health cooperators.”
Oak wilt can spread in two ways, above the ground through the movement of fungal spores by sap-feeding beetles to wounds in oak trees, or below ground through the grafted roots of neighboring oaks.
Treatments for oak wilt disease are often costly and damaging. They involve cutting and removing trees with the disease, including many adjacent apparently uninfected trees and disrupting the root systems using heavy equipment.
To test the oak wilt rapid response treatment, researchers needed to infect oaks with the disease. To accomplish this, climbers drill into the branch and add the fungal disease to mimic a natural infection. Following artificial infection, forest health managers girdle the trees at predetermined times to prevent the oak wilt infection from advancing down from the crown into the roots and spreading throughout the root systems to other trees.
Girdling — when bark and some wood materials are removed from a ring around the tree’s trunk — has been shown in recent testing to be an effective means in stopping the spread of oak wilt into the tree’s roots and protecting other trees in that area.
“We normally look for trees with easy access,” Valento said. “For these trees they were very specific. They were not in the optimal places. They were looking for 18-inch-diameter oak trees surrounded by other oaks, in addition to other factors. We were struggling on some of the trees to find the optimal branch.”
The program was implemented this summer in Minnesota, Wisconsin, and Michigan oak trees. The group will conduct one more summer of treatment, then monitor the select trees for five years for effectiveness. Following that duration in 2028-2029, they will publish the results and techniques for private landowners and urban communities to apply to their forests.
Forest managers also remind people to please not move firewood, which can contribute to the spread of diseases to other areas.
Map showing counties in the eastern US with oak wilt (shown in red), as of 2022. USDA Forest Service Image-Eastern Region State, Private, & Tribal Forestry
For additional information on the project, please visit:
Oak Wilt in the Northeastern and Midwestern States (arcgis.com)
