Emerald Ash Borer – What You Should Know

Emerald Ash Borer (EAB) is an invasive insect first discovered in Detroit, Michigan in 2002.  It attacks all varieties of ash trees.  EAB is now found throughout Ohio, which is under quarantine to help prevent its spread.  EAB has recently been found in, and is spreading throughout The City of Gahanna.

What to look for: Once infested, trees may show little sign of the pest for the first year or two.  The larval stage of EAB feeds under the bark of trees, cutting off the flow of water and nutrients. They emerge as an adult the following year leaving a D – shaped exit hole (PIC).  Adults are dark metallic green, ½” in length and 1/8” wide (PIC).   The EAB flies from early May until September.  Ash trees that become infested with EAB typically die within five years. 

Dying ash trees lose strength more rapidly than other trees such as maple or oak.  Ash is also self-pruning; dead branches fall as they die, sheering close to the main stem.  Self-pruning trees can be a hazard, as branches fall without warning, placing residents and property at risk.  Also, as the main tree stem dies, large portions of the tree may collapse, creating a hazardous condition. This is important because as trees become a hazard, removal needs to be addressed to avoid liability issues.

How many ash trees are in Gahanna? The City of Gahanna has 1660 inventoried ash trees on city-owned property or in right of ways such as tree lawns.  Private properties have not been inventoried. To find out if your tree lawn has an ash tree, visit the GIS Mapping system on the City’s website, www.gahanna.gov, locate your address, then check the “Street Trees” box in Map Layers.

Ash trees on private property, including tree lawns, are the responsibility of the homeowner. It is recommended that if the EAB is suspected, residents should consult an arborist immediately.  Residents are invited to visit www.emeraldashborer.info for reference information and useful links.  The City recommends private property owners remove infested trees on their property and replace them with a resistant species or implement a treatment program as prescribed by a qualified arborist.

What is being done: Due to budget constraints, the City only has the ability to address infested trees on an as needed basis.  Trees on public property deemed a hazard by the City arborist will be removed.  As funds are available, the stumps of the removed tree will be ground and a new tree of a different species will be planted.   The City plans to treat trees in parks with pesticides for EAB on a case-by-case basis and based on funding levels. 

What can I do with the wood? Ash wood is safe to burn in fireplaces and other legal locations. Infested wood can be disposed of by chipping it to 1” or smaller and recycle it with other yard waste.  The movement of ash trees, lumber or firewood from Franklin County and Ohio is prohibited without a permit.