Mass. Oak Tree Epidemic

Freetown, Mass. has spent nearly $60,000 removing dead trees like this oak, but the cleanup is far from finished.

After repeated attacks from leaf-eating caterpillars the past few years, thousands of oak trees are either dead or dying in Southern Massachusetts.

Oak trees are dying in epidemic numbers this year, but their fate was sealed years ago, experts said. Outbreaks of winter moths, gypsy moths and forest tent caterpillars in 2004 and 2006 weakened the trees’ natural defenses.

“It’s guaranteed that the trees dying off this year have been defoliated multiple years before,” said G.B. Knowles, a certified arborist based in Fairhaven. “A lot of times, when a tree dies, it slowly declines. These trees are going quickly and within a year, the bark starts to fall off indicating they are dried out and weakened.”

Oaks also sustain damage from black beetles that bore into the bark and absorb nutrients, along with shoestring root rot, a fungus that invades the base of the trees, said Tchukki Andersen, an arborist with the Tree Care Industry Association in New Hampshire.

“More than anything, these insects are breeding and they just keep spreading to the next oak and then the next oak,” said Douglas Boucher, owner of Ups & Downs Tree Service in Haverhill, which services SouthCoast in addition to the Boston area. “If we don’t do something, it will just keep on going.”

Arborists say landscape managers can save their oaks — if they act quickly. Spraying trees with insecticide is the best way to protect them, Mr. Knowles said. His company sprays oaks with Bacillus thuringiensis, commonly referred to as BT, an environmentally safe bacteria that is lethal to some insect larvae when ingested.

He also recommended wrapping sticky bands around the tree trunks as a way to trap caterpillars as they migrate toward the leaves. He said the bands are available in most home and garden stores.

Experts caution that inappropriately applying chemicals can be hazardous to some trees. The best call is to consult with professional arborists before making any decisions. But it may be too late to save distressed oaks. “If the damage has already started, it’s pretty much done,” Mr. Boucher said. “It’s just time to say goodbye to the tree.”

Source: southcoasttoday.com