Bangor staff present preemptive emerald ash borer plan after regional detections

Bangor Public Works staff and interns on Monday presented a preemptive emerald ash borer (EAB) management plan and a newly completed street-tree inventory that shows ash trees account for roughly 20.3% of the city—s publicly managed urban canopy.

The inventory and draft management plan were produced by the Public Works Forestry Division in collaboration with the University of Maine School of Forest Resources. "Emerald ash borer does pose a very significant threat to all ash in Bangor," said Sofia Cameron, a master—s student who led the inventory work this summer for the city.

The nut graf: city staff said acting before a confirmed infestation will allow Bangor to prioritize trees for treatment, plan removals and replacements, and design outreach to private-property owners. The Maine Forest Service has been monitoring EAB in Maine since 2018, with detections in Stetson (2022) and Herman (2023); presenters said Maine is likely to see additional detections and urged preemptive steps.

City Forester Ben Aruta and the four University of Maine interns walked and logged every publicly owned street and right-of-way tree using Field Maps GIS tools. The inventory lists 8,574 actively managed public trees and identifies 1,740 ash trees (about 20.3% of the public tree stock) as of 2024. The interns recorded species, GPS location, diameter at breast height, a 1-to-5 condition rating and whether a tree intruded on utilities, sidewalks or private property.

Cameron explained EAB biology and identification: the insect (Agrilus planipennis) kills ash by feeding on the phloem, producing serpentine galleries under the bark and creating D-shaped exit holes. She said EAB has a reported mortality rate of about 98% for susceptible ash trees and is difficult to detect early because initial infestation begins in the canopy.

Staff outlined a four-part management approach that they plan to recommend to the council: (1) prioritized removal of trees already in poor condition or posing safety risks; (2) treatment via trunk injections for high-value, vigorous trees (staff noted trees can remain eligible for treatment until roughly 40% leaf loss); (3) replacement with climate-hardy, site-appropriate species and managed replanting to increase species diversity; and (4) continued monitoring using both Maine Forest Service traps and locally deployed monitoring (the city hopes to involve high-school students in a community-monitoring program).

Cameron said the city intends to plant species tolerant of future climate conditions and to avoid planting large-canopy trees under power lines. She also noted the cultural importance of brown ash to Wabanaki people and said the city will consult tribal leaders and basketmakers on any actions that might affect culturally important ash resources.

Staff emphasized outreach and private-property coordination: they plan to add a private-tree reporting function to the city's ClickFix system, pursue federal and state funding options to assist residents with dangerous private trees, and use an ArcGIS "story map" to let residents view the public-tree inventory and track treatment priorities.

Public Works staff said treatment work for trees already identified as eligible is planned to begin next spring and summer, and that the student capstone and a finalized management plan are expected to be presented to the full council in 2025 for consideration and potential adoption. No formal council vote was recorded at the committee meeting.

Ending: staff asked for council support to move the plan forward and for permission to continue outreach and coordination with state partners; staff and interns said the inventory provides the city with the data needed to prioritize action if EAB arrives locally.