Jan. 2024 update: Tree removal work in the Bird Hills Nature area will begin on Monday, Jan. 15 and should conclude by Friday, Jan. 26, 2024. Click here to view a post on Facebook about the Oak Wilt situation in the park.
On Aug. 28, 2023, testing confirmed suspected oak wilt infections in a cluster of several Northern red oaks (Quercus rubra) in the Bird Hills Nature Area.
The State of Michigan explains oak wilt:
" . . .kills healthy red oaks. White oaks can also be affected but are more resistant and less vulnerable to mortality from the disease. Once a red oak becomes infected with the oak wilt fungus, the tree will die, and
there is no treatment to save the infected tree. Once an oak wilt infection is confirmed, however, treatments are available to save surrounding oaks and stop the spread of this disease."
Oak Wilt is not new to Michigan or Washtenaw County, however this is the first time it's been identified in a nature area within the City of Ann Arbor.
The forestry department working in collaboration with the Natural Area Preservation (NAP) division is taking steps to develop and implement the appropriate remediation plan for Bird Hills Nature area. This plan will require both above and below ground steps to ensure the infections are addressed and don't spread to other trees.
Belowground, the City is:
- Trenching a perimeter around the infected and potentially-infected stand of red oaks. Trenching will sever the root systems through which the infection spreads.
Aboveground, the City is:
- Removing all the red oaks within the trenched perimeter. Currently, the recommended trenching perimeter would result in approximately fifty-five (55) red oaks being cut and removed. This will result in the loss of significant tree canopy in the remediation area.
The remaining canopy will be comprised of several native and mature non-oak tree species that will not need to be removed, as the infection only spread through oaks. City staff plan to have the trenching portion of the work completed by early November and the tree felling done by the end of January, 2024.
Visitors to nature areas should refrain from walking in marked areas, to avoid trip hazards, and should never move any flags or signage.
What residents can look for
Oak wilt can't be discovered by eye, only it's symptoms are visible and the fungus only confirmed by lab testing. To learn more about what to look for, please visit this Oak Wilt 101 page.
If you see a tree that you suspect may be suffering from oak wilt, please utilize the A2 Fix It page or the A2 Fix It mobile app on your phone to notify city staff to investigate further.
