Claremont prepares for insect attack on ash trees

By GLYNIS HART
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CLAREMONT – The emerald ash borer isn’t here, but it soon will be. The bright blue-green invasive insect has been confirmed as close as Bradford, and is spreading west from infested forests in the center of the state. The State of New Hampshire is within the federal quarantine zone, meaning firewood cannot be moved from here into Maine. 

The emerald ash borer burrows beneath the bark of ash trees and usually kills the tree within three or four years. The infestation in a tree can be spotted by looking for “blonding” where the gray bark has peeled to the blond pith beneath; lots of woodpecker activity, as the birds feed on the bugs, and in late stages by dead branches. 

Ironically, the city planted the ash trees nearly 30 years ago to replace the stately elm trees that used to lend green shade to downtown. Those trees also died because of an invasive — an air-borne fungus, the Dutch elm blight. 

“They were planted to recapture some of the glory,” said Gary Dickerman, chair of the conservation commission. 

Like many cities in the infected zone, Claremont will be on the hook for those trees if they die and start dropping limbs or falling over. 

Steve Wood and Gary Dickerman of the city conservation commission recently conducted a survey of the ash trees in the downtown area. They counted 21 ash trees, totalling 259 diameter inches, in the area immediately around the Broad Street park. 

Dickerman told the conservation commission at the Dec. 20 meeting that he’d given the survey results to forester Lee Stevens, whose Log Cabin Nursery handles invasive plants as well as other landscaping. 

“He said it’s $10 per diameter inch to treat the trees,” said Dickerson. “He will put together an estimate to treat and/or remove the trees.” 

A few of the downtown ash trees are not in great shape anyway, with “car fender and snowplow” damage done to their trunks. “Most have done pretty well,” said Dickerman. 

“We’ll wait to hear from Lee and then we’ll decide what we want to present to the city council,” said Dickerman. 

White ash, green ash, black and brown ash trees are all susceptible to the EAB; mountain ash is a member of the rose fammily and not a true ash (genus Fraxinus), therefore is not affected. Ash has compound leaves, with ten or twelve leaves paired along a common stem.  Most other trees have alternate branching where buds and twigs are staggered along the branches. The trees also have a distinctive diamond-pattern bark. 

Ash trees form an important part of northeastern hardwood forests, being straight-grained and therefore easy to split for firewood. They grow quickly and are somewhat salt-resistant, making them ideal for city plantings. 

A 2012 study published in the American Journal of Preventive Medicine found  an increase in mortality related to cardiovascular and lower-respiratory-tract illness in counties infested with the emerald ash borer. The magnitude of this effect was greater as infestation progressed and in counties with above-average median household income.