Frequently Asked Questions

Yes—unless they are treated with insecticide for the lifetime of the tree by a licensed arborist. Untreated ash trees are typically lost within about ten years of detection. In Watertown, some boulevard trees will be treated to preserve shade while new trees grow, but the long-term goal is to reduce ash so that it makes up less than 10% of the overall canopy in 20 years.

If we cut every ash tree at once, neighborhoods would lose decades of shade, beauty, and environmental benefits overnight. Removing trees is also the most expensive part of EAB management. By treating healthy, well-structured trees, we can keep a larger percentage of our community's canopy in place while young replacement trees grow.

Treating trees protects them for many years, but it requires ongoing costs and staff time. Not every ash is healthy enough, safe enough, or well-placed to justify the investment. By focusing treatments on select ash trees, we make sure those dollars provide the greatest benefit to the community.

1. By treating some trees and removing others, we keep about half of the ash canopy standing and healthy while new trees grow. This preserves shade and character in our neighborhoods, saves money by spreading out costs, and gives City crews a manageable workload.

If you have ash trees on your private property:

• Identify them — ash trees have compound leaves with 5–11 leaflets and opposite branching.
• Decide whether to remove or treat on private property. Contact a licensed arborist.
• Take action early — waiting will increase costs and limit options.

 For boulevard trees, no action is required from homeowners. Forestry staff will handle removals and treatments.