Bath Anticipates Arrival of Emerald Ash Borer; Develops Management Plan

Date: November 5, 2019
Bath, Maine 04530

In the wake of a National outbreak, Emerald Ash Borer (EAB) was recently discovered in Portland.  The discovery of this pest in Maine’s largest city raises the question of “when” will this destructive pest arrive in other parts of the State. Fortunately, the City of Bath has been planning for its arrival since it was first detected along the Maine/New Hampshire border.

EAB affects trees by tunneling through its inner bark and cutting off the flow of water and nutrients, killing the tree in five years or less. Like many cities and towns in Maine, Bath has large numbers of planted and naturally occurring ash trees in the forests located in and around its developed areas. Because the trees are tough and acclimate well to various growing conditions, they have been incorporated into street design for decades. They are often called upon to provide shade, filter air, and provide a glimpse of nature in the least-favorable planting sites within our built landscape, like congested sidewalk pits, and areas where the extremes of summer’s heat, winter’s cold, and snow banks filled with road salt make life nearly impossible for most tree species.

Ash trees make up 6% of the inventoried urban forest within Bath and just 4% of Maine’s total hardwood forest resource, but don’t let these percentages fool you. Ash trees provide tangible, fiscal benefits to Bath to the tune of $480,000 a year. Even one ash tree with a single 10” diameter trunk can provide up to $99/year in benefits to a city or town through its ability to improve air quality, absorb storm water, save electricity, and increase property values1.

The City Arborist, along with the Bath Community Forestry Committee (BCFC), has drafted a management plan to deal with the eventual arrival of EAB. The plan includes updating the City’s tree inventory and developing the BathTreeMap2, an online tool that allows users to see the locations of various tree species within the City and highlights to locations of City-owned ash trees. Because the invasive insect is attracted to stressed ash trees in particular, several “trap” trees, which have been girdled and peeled, are also being monitored within the City for signs of the beetle. Bath will soon begin to assess ash trees growing on City property and remove weak or undesirable ones while treating those with historic value and other desirable traits.

Local property owners are encouraged to visit the Maine Department of Agriculture, Conservation and Forestry’s webpage on the EAB for helpful information on identifying and preparing for the pest. Additional questions or EAB sightings may be sent to the City Arborist at

1 Source: National Tree Benefits Calculator. Retrieved from    

2Access to BathTreeMap may be found on the City of Bath website’s Forestry Division page.