Photo credits: Brian Sullivan, USDA APHIS PPQ, Bugwood.org; R. Jeanette Martin, flickr.com and used with permission via Creative Commons license 2.0; University of Minnesota
Number of ash trees in yards, parks and streets throughout Hennepin County
Number of ash trees that are susceptible to emerald ash borer and will die unless treated
Most residents live within 15 miles of an infested ash tree.
See where emerald ash borer has spread in Hennepin County (GIF)
There are several varieties of ash trees in Hennepin County – green, white and black – and all are susceptible to emerald ash borer.
Look for the following characteristics to determine if your tree is an ash tree:
Branches grow directly opposite from one another.
Compound leaves, or multiple leaves on one stalk joined to a branch. Leaves commonly have 5 to 9 leaflets.
Bark with diamond-shaped pattern.
Seeds are oar-shaped samaras that typically hang in clusters.
Photo credits: Lindy Buckley (ash leaves); Paul Smith of the Duncannon Appalachian Trail Community (ash tree bark); a200/a77Wells (ash seeds)
The following signs may indicate that an ash tree is infested with emerald ash borer.
Leaves on the top or one part of the tree start dying.
Sprouts growing from the roots or base of the tree indicate it is stressed.
Increased woodpecker activity with sections of the bark stripped away.
Adult beetles leaving the tree create D-shaped exit holes.
Larvae feeding on the tree's tissue leave a sperentine pattern underneath the bark.
Treatment with an insecticide is an option to preserve ash trees of high value. See our decision guide for managing ash trees (PDF) to decide what approach to managing ash trees works best for you.
Learn how treatment works and how to decide if it's the best option for your trees.
Whether you are treating or removing your trees, you should work with an ISA-certified arborist. These arborists are trained in proper tree care by the International Society of Arboriculture.
Photo credit: R. Jeanette Martin, flickr.com and used with permission via Creative Commons license 2.0
Any ash tree not being treated will eventually need to be removed and disposed. A dead tree should be removed before it becomes a hazard.
Trees provide numerous benefits including improving air and water quality, reducing soil erosion, increasing wildlife habitat, providing savings in heating and cooling, and improving health. So planting new trees in place of any you remove is a great idea.
Photo credit: University of Minnesota
This resource is part of Hennepin County’s effort to maintain a healthy tree canopy and increase awareness about the threat emerald ash borer poses to ash trees.