Eversource ramps up tree-trimming efforts

Eversource crews chipping tree branches after cutting down several trees on Scobie Pond Road in Derry on Friday.

DERRY — Crews with Eversource Energy’s vegetation management team felled their 313th tree on Scobie Pond Road Friday since trimming of roadside trees near their Derry substation began about four weeks ago.

The team’s manager, Bob Allen, said the work is part of an “enhanced tree trimming” effort, meaning they are cutting ground to sky to make sure there are no trees hanging over the power lines on this stretch of road.

The work on Scobie Pond Road is particularly critical since it is so close to a substation, the loss of the “backbone” powerlines there would result in thousands of people losing power.

Allen said the work is part of regular maintenance that will result in about 15,000 trees being cut along more than 2,700 miles of power lines this year.

But the crews are likely cutting more trees than they would be otherwise given a confluence of unusual weather conditions.

“Here we are on September 28 and everything is green,” Allen said, saying even lawns would have normally turned yellow by now.

Grass, requiring far less water than a tree, is an indicator for foresters in determining when there is too much or too little water.

Root structures for trees have been weakened by droughts in three of the last four years, but this year has seen the hottest summer and the rainiest August on record for the state, Allen said. That has caused trees to grow for a longer period, often filling out foliage at the top, making the trees top-heavy and usually leaning toward the sunlight, which often means in the direction of power lines.

The added rains can also make the ground at the base of the trees soft and provide the trees with less of a purchase on the soil.

Allen said the growing season, defined by the period between the last and first frost, has increased tremendously. The 2017 season was 30 days longer than in 2016, which Allen said is highly unusual.

While he can’t say with confidence if these conditions mark the beginning of a trend, he does think it will have an immediate impact this winter.

“I think we’re going to see some damage this winter,” Allen said. “That’s what we’re trying to get ahead of.”

White pines are the tallest trees to grow along roadsides, Allen said. They grow as high as 120 feet, while power line poles are about 45 feet high.

Other stressors such as invasive insect species can complicate things. New Hampshire is still struggling with the introduction of the Emerald Ash Borer. Allen said ash trees make up only 6 percent of New Hampshire’s forests, but up to 30 percent of roadside trees.

While the Granite State isn’t struggling much with gypsy moths, Connecticut and Massachusetts are still experiencing the lingering effects of the nesting insects defoliating oak and other trees during drought years. They thrive in droughts, Allen said, because their natural predator is a mold.

Eversource is investing $44 million in tree trimming this year.