Oak Wilt at Wildwood Preserve Metropark

Oak wilt is an aggressive disease caused by an invasive fungus that infects an oak tree’s vascular tissue (xylem), which prevents water from reaching the tree’s leaves.

This is an example of a leaf from a red oakthat has been stricken by oak wilt. This water-starved leaf condition is also called trifoliation.

This is an example of a leaf from a red oakthat has been stricken by oak wilt. This water-starved leaf condition is also called trifoliation.

Red oakred oak tree

White oaks are moderately resistant to the disease and may live several years after being infected.

red oak leaves (pointy tips)

red oak leaves (pointy tips)*

*In northwest Ohio red, black, scarlet and pin oaks are well-known forhybridizing and will here be collectively referred to as red oaks.

red oak leaves (pointy tips)

White oak leaves (rounded tips)

The primary way oak wilt is spread is from root grafts thatform underground between two trees, allowing fungus to spread from an infected tree to a healthy tree.

The second way oak wilt is spread is when fungal spore mats form under the bark of an infected tree. If that tree’s bark bursts a sap-feedingbeetle may be attracted to the fungus, feed on the spore mat, then flyto a healthy tree and infect it by entering through a wound in that tree.

The western part of Wildwood Preserve (about 200 acres) is dominated by a continuous canopy of about 30,000 red oaks trees.

During the spring of 2014 this area was monitored by Metroparks’ natural resource professionals.

After more trees were found dead and dying, samples were collected by the OSU Extension which confirmed that sporesof oak wilt were present.

Our MethodsAn aerial survey confirmedthe ground survey results andlooked for other oak wilt“hot spots.”

Management methods:

Sanitation:Removal of potential spore-producing trees and…

…contain the spores within those trees.

Root graft disruption

By using a tractor-mounted trenching tool called a vibratory plow to break root grafts between an infected tree and other nearby oak trees.

To separate infected roots from healthy roots.

A rather clean look after treatment that will be imperceptible in a couple of years.

The oak wilt outbreak needsto be contained now…

…to ensure the health of Wildwood Preserve’s beautiful oak forest, forever.