Boston declares war on green invader bug; several hundred doomed street trees to be sacrificed, in part to keep them from falling on people's heads

The mayor's office today declared a war that could last several years against the invasive and voracious emerald ash borer. Residents will see the first major evidence of the battles to come this winter, when Boston arborists chop down several hundred "dead, dying, or significantly damaged" ash trees across the city.

The emerald ash borer lays eggs on the bark of ash trees - and only ash trees - which then hatch into larvae that burrow into the trees, killing them. The bugs also bring woodpeckers, which further damage, or "blond" the trees, by hammering off bark in their search for the delectable larvae.

Officials say that now that they're here, the bugs won't be eradicated; the hope is to manage the infestation by reducing their numbers. In the spring, arborists will return to city streets to inject the remaining health trees with a pesticide.

Boston currently has 1,817 public ash trees, the parks department reports.

Emerald ash borers, native to Asia, were somehow imported into the Midwest in the 1990s. They were first detected in Massachusetts in 2012, out in Dalton, in the Berkshires, but just two years later, they showed up at the Arnold Arboretum on the Jamaica Plain/Roslindale line.

The city says there is now evidence of the bugs in Allston-Brighton, Dorchester, Fenway-Kenmore, Hyde Park, Jamaica Plain, Roslindale, Roxbury, Mattapan and West Roxbury.

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.

The trees that are cut down will be replaced with new trees, the city says.

The parks department acknowledges watching trees get cut down can be traumatic, but says it's less traumatic than having limbs or whole dead trees falling on somebody or somebody's car.