Protecting Tulsa's Trees

Emerald Ash Borer Threat in Our Community

The invasive emerald ash borer (EAB) has recently been confirmed in Broken Arrow, placing ash trees in our region within its typical spread range. EAB is a non native beetle, known for causing extensive and often fatal damage to ash trees across the United States.

How EAB Spreads

These beetles can fly up to 15 miles per year on their own, but they spread much farther when transported inadvertently in firewood, shipping containers, logging activity, and other wood moving operations. Because of this, they can appear suddenly in new areas.

What EAB Does to Trees

Adult beetles lay eggs on the bark of ash trees. When the larvae hatch, they bore into the tree and feed on the phloem and cambium layer under the bark, disrupting the tree’s ability to move water and nutrients. When they mature, they exit through small D-shaped holes in the bark. Once heavily infested, ash trees decline rapidly and become brittle, posing risks in parks, yards, and public spaces.

Current Local Impact

Tulsa Parks Forestry crew has initially identified over 500 trees in maintained areas within Tulsa Parks, while there are more in natural areas across Tulsa. 

• Initially 411 were considered as potential candidates for treatment and preservation.
• Mohawk Park contains around 40 ash trees.
• Green ash and white ash species are both present locally.

How to Identify Emerald Ash Borer Activity

Recognizing the early signs of emerald ash borer (EAB) can help slow its spread and may give your ash tree the best chance of survival.

Key indicators include:

• D-shaped exit holes in the bark
• Thinning foliage and canopy dieback
• S-shaped galleries beneath the bark
• Increased woodpecker activity

What Residents Can Do:

• Contact an International Society of Arboriculture certified arborist to confirm ash species and evaluate tree health.
  • These can be found by visiting: https://www.treesaregood.org/Find-an-Arborist
• Avoid moving firewood or untreated logs.
• Explore treatment options as soon as possible if you want to preserve your ash trees.
• Consult multiple tree care companies for estimates or additional information.

Treatment Options

Property owners who wish to preserve healthy ash trees should act promptly. Treatments are most effective in the spring when trees are fully leafed and actively transport nutrients.

Common treatment methods include:

• Trunk injections using emamectin benzoate, providing up to two years of protection.
• Bark sprays, which need to be reapplied annually.
• Soil drenches, which need to be reapplied annually.

Treatment needs are based on the tree’s diameter - certified arborists can determine appropriate methods. In many cases, treatment is more cost effective than tree removal, especially as dead ash trees become structurally unstable.

What the City Is Doing

To preserve as much of our urban canopy as possible, Tulsa Parks has begun a large-scale treatment effort for all suitable ash trees in our park system.

Our forestry team is injecting all identified approximately 400 ash trees in parks across the city. Trees are being treated using trunk injections of emamectin benzoate, the method proven to provide up to two years per treatment.

Each tree receives a series of small injection sites around the trunk, determined by the tree’s diameter. This proactive treatment program is significantly more cost-effective than widespread tree removal and helps maintain the health, safety, and beauty of our parks.

Our community is committed to protecting its urban tree canopy. Early detection and action are key to managing the emerald ash borer and reducing long-term impacts. 

More Information

Oklahoma State University (OSU) Extension has some additional, informative information, for those wanting to learn more:

https://extension.okstate.edu/fact-sheets/emerald-ash-borer-in-oklahoma-what-to-look-for-and-what-to-know