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Ash Tree care plan for Boston announced

The Emerald Ash Borer is a threat to the City of Boston’s Ash Trees.

Mayor Kim Janey and the Boston Parks and Recreation Department today announced measures being taken to slow the spread and protect Boston’s public street trees from the Emerald Ash Borer. This invasive beetle lays eggs on the bark of ash trees and upon hatching, the larvae burrow deeper in the tree, killing it. The pest only feeds on ash trees.

Adult Emerald Ash Borer beetle

(Photo: Debbie Miller, USDA Forest Service)

The City of Boston will manage the infestation by treating healthy trees on public property to prevent infection and removing trees that are dead, dying, or significantly damaged. Several hundred street trees will be removed this winter while the trees are dormant, and preventative injections will begin next spring when healthy trees are becoming more active. Sites where trees have been removed will be prioritized for new tree plantings in the next planting season. Managing the Emerald Ash Borer infestation in Boston will take place over several years.

“Dead, dying, and damaged trees pose a significant public health and safety threat to Boston’s communities,” said Mayor Janey. “The City Arborist is currently working to determine which public street trees have been infested with the Emerald Ash Borer. It’s crucial that we save as many trees as possible with smart management decisions to protect our City’s green spaces for generations to come.”

Ash tree receiving preventative treatment for Emerald Ash Borer

(Photo: David Cappaert,

The Emerald Ash Borer has been spreading since it was first found in the Arnold Arboretum in 2014. The invasive beetle has been identified in the neighborhoods of Allston-Brighton, Dorchester, Fenway-Kenmore, Hyde Park, Jamaica Plain, Roslindale, Roxbury, Mattapan, and West Roxbury, as well as the Arnold Arboretum, Franklin Park and the Muddy River area. Ash trees around the City are beginning to show outward signs of infestation, which include D-shaped exit holes in the bark of ash trees, ”blonding” from woodpecker feeding, dieback in the upper third of the tree canopy, and sprouting at the base of the trunk.

Emerald ash borer adults chew D-shaped emergence holes to exit from ash trees

(Photo: Debbie Miller, USDA Forest Service)

“Blonding” from bark removed by woodpeckers searching for emerald ash borer larvae and pupae

(Photo: Steven Katovich,

Basal sprouting on an ash tree in the Fenway neighborhood of Boston

(Photo: Max Ford-Diamond)

“Understanding canopy loss is the first step in addressing issues affecting Boston’s trees—like climate change, development, pests, and disease—and how those factors intersect,” said Reverend Mariama White-Hammond, Chief of Environment, Energy, and Open Space. “That’s why the Parks Department is developing a road map to powerful, equity-centered policy changes that will preserve and expand our tree canopy—the City’s first Urban Forest Plan.” 

The City’s Urban Forest Plan’s initial phase, a comprehensive tree inventory, was completed in September and revealed that Boston is home to approximately 1,817 public street ash trees, which represent about 4.3% of the city’s total street tree population. The Plan’s recommendations will also include increased funding and staffing for tree care and to more effectively respond to invasive insects like Emerald Ash Borer.

“While tree removals are always challenging to witness, they are necessary to protect healthy trees and to stop the spread of Emerald Ash Borer,” said Parks Commissioner Ryan Woods. “Dead trees, with their brittle wood, quickly become a safety hazard.”

“Since its introduction into the U.S. Midwest in the 1990’s, the emerald ash borer has killed millions of natural and cultivated ash trees. Spreading to Massachusetts in 2012, it was first detected in Boston here at the Arnold Arboretum through a rigorous monitoring program in partnership with the DCR and the City. The City’s Urban Forest Plan aims to diversify, expand the tree canopy, and prepare for the challenges of tomorrow—a key step toward a more resilient and sustainable urban forest,” said Andrew Gapinski, Head of Horticulture at the Arnold Arboretum and member of the Community Advisory Board for the Urban Forest Plan. “The emerald ash borer is here to stay, and best management practices of surveying the City’s ash trees for signs of the beetle, removal and replacement of trees in decline, and treatment of trees in good health is essential to saving as many ash trees as possible. EAB is just one of many introduced pests that have devastating effects on our forests, landscapes, and communities – and it certainly will not be the last.”

The Boston Parks and Recreation Department cares for public street trees and park trees. If you believe you have seen an infested ash tree on a public street or park, contact 311. Private property owners should learn to recognize ash trees, check for signs of infestation, and contact a certified arborist for preventative treatments. The Massachusetts Department of Conservation and Recreation coordinates the Emerald Ash Borer response at the state level and provides resources on their website.

The Parks Department will hold two webinars scheduled for 12:00 p.m. and 6:00 p.m. on October 28. Additional information on Emerald Ash Borer, and the webinar registration form, can be found on our caring for Boston's trees website.

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