No, emerald ash borer has not been found in Highlands Ranch. However, detecting emerald ash borer can be difficult when pest populations are small. Damage to trees is hidden under the bark and tree decline is gradual.

Emerald ash borer was first found in Boulder in September 2013. Since then it has also been detected in the cities of Gunbarrel, Longmont, Lafayette, Lyons, Superior, Broomfield, Westminster, Louisville, Erie, Arvada, an area near Berthoud, Thornton, an area north of Fort Collins, Carbondale, Littleton and Centennial. The insect is expected to spread in upcoming years. It was originally detected in Michigan in 2002 and has since been confirmed in 36 states.

• Staying in tune with regional trends, the Metro District forestry team hasn't planted any new ash trees in Highlands Ranch in at least 15 years. Tree diversity is a priority for any new tree plantings, which benefits the health of our overall urban forest.
• As occurrences of emerald ash borer were confirmed closer to our community, the forestry team prioritized high value, healthy ash trees for treatment. These high priority trees include large trees in Metro District parks that shade ballfields, playgrounds and other spots frequently used by visitors. Trees are treated by forestry staff with injections or trunk sprays as dictated by each situation. While a significant portion of park trees will be treated to protect against emerald ash borer, the majority of ash trees on Metro District property will not be treated.
• If any ash trees are suspected to have emerald ash borer, forestry technicians conduct branch sampling to look for signs of the insect. Emerald ash borer has not been found on Metro District property.
• Metro District foresters share information with our community to protect our urban forest. They are happy to answer questions or direct residents towards appropriate resources.

Ash trees have compound leaves, meaning there are five to nine leaflets on each stalk. Leaflets are smooth or finely toothed along the edges. Seeds on female trees are paddle-shaped. Branches and buds grow in pairs, directly opposite from each other. Mature bark displays diamond-shaped ridges.

• Use this flowchart from Colorado State University Extension to differentiate ash trees from other common shade trees.
• Colorado State Forest Service and Colorado State University Extension also offers a webpage with helpful resources for ash tree identification.

Symptoms of infestation include:

• sparse leaves or branches in the upper part of the tree
• D-shaped exit holes about 1/8 inch wide
• new sprouts on the lower trunk or lower branches
• vertical splits in the bark
• winding S-shaped tunnels under the bark
• increased woodpecker activity

The Colorado Department of Agriculture and Colorado State University Extension offer a helpful decision guide for homeowners. When deciding if ash trees should be left alone, removed or treated:

1. Inventory your ash trees and determine how many you have and where they are located.
2. Figure out if some are worth saving:
   • Are the valuable to the landscape or owner?
   • Are they healthy and have few signs of EAB?
   • Are they located on the right site?
3. Consult with a reputable tree care professional to help evaluate your trees and treat those you'd like to save. Be sure to get at least two estimates, hire a certified licensed professional and ask for references and insurance.

Homeowners can also preemptively remove less desirable ash trees and replace them with more diverse species.