Integrated Vegetation Management Techniques are the key to Power line corridors being viable habitat for shrub-loving species like the endangered New England Cottontail Rabbit

The Nature of Powerlines

by Madeline Bodin 

Illustration by Adelaide Tyrol

In Pittsford, Vermont, a state-threatened sunflower nods in the breeze. Near Concord, New Hampshire, the tiny, federally-endangered Karner blue butterfly flits from one flower-spike of wild lupine to another. In southeastern New Hampshire, a state-endangered New England cottontail twitches its nose in a thicket.
Elsewhere in southeastern New Hampshire, an eastern towhee, once considered the most rapidly declining songbird species in the Northeast, rummages through dried leaves. And in Dummerston, Vermont, state-endangered scrub oaks punctuate a prairie-like grassland that includes the state-endangered Greene's rush and rare clustered sedge.

While each of these habitats is different – woodland edge, sandplain, shrubland, and savannah – they share one important characteristic: electric powerlines overhead. In each case, these rare species have found a home in a maintained powerline corridor.
With VELCO, the Vermont Electric Power Company, beefing up its transmission backbone in southern Vermont, and Hydro Quebec planning new lines between its dams in northern Quebec and the population centers of southern New Hampshire, powerline construction is in the news.

It's easy to see powerlines as all good or all bad. They bring us electricity, which is good, but they disturb and alter the environment, which seems bad indeed. But that environmental alteration has many subtleties, and some wildlife managers praise well-managed powerlines for providing valuable habitat for dwindling species.

"Regionally, from Virginia to Maine, shrubland species are one of the most threatened groups," says Steven Fuller, a terrestrial ecologist for the New Hampshire Fish and Game Department. Powerlines play a role in preserving those species, he says.
That powerlines turn our forested landscape into other types of habitats is an accident.

 Power companies are not trying to create habitat diversity when they build powerlines, they just don't want tall trees to interfere with the wires.The power companies have many ways of achieving this, but one technique that is proving beneficial for rare species is called "integrated vegetation management." Jeff Disorda, supervisor of right-of-way management for VELCO, says that the goal of integrated vegetation management is to eliminate trees over 12-feet tall from the powerline corridor using methods that are ultimately self-sustaining.

Just cutting the trees won't do, he says, because hardwood trees, such as maple, will send up shoots from their stumps. "We call them incompatible species," he says. Herbicide, sprayed from a backpack on to stumps or the base of the tree, kills off the trees' root system. The compatible species, such as shrubs, ferns, grasses, and blueberries, are left alone and fill in where trees once grew.
"Hardwood trees will have a harder time seeding back in to that," says Disorda.

Over time, less maintenance is needed as low-growing plants become established. And in some special areas, rare ecosystems can be established.

For example, in parts of New Hampshire, dry, sandy soils would form pine barrens if wildfires weren't suppressed. Here, powerline maintenance takes the place of fire, allowing a sandplain ecosystem to emerge, hosting wild lupines, Karner blue butterflies, and state-endangered frosted elfin butterflies.

When it comes to endangered shrubland species, it turns out the bigger the powerline, the better. David King, research wildlife biologist with the Northern Research Station of the U.S. Forest Service in Amherst, Massachusetts, says that of the 40 species of shrubland birds in New England, the ones most sensitive to the size of the shrubland are cause for most of the concern. Prairie warblers and field sparrows, whose populations are declining, are found only in the widest power line corridors.

"In New Hampshire, not all the utility companies use integrated vegetation management, for fear of public outcry [over using herbicides]," says Fuller. He believes, however, that a careful use of chemicals can result in a lighter environmental impact overall. The alternatives, like cutting all vegetation to the ground every few years, can be even more detrimental.

And, speaking not just about herbicide application, but all powerline maintenance, he adds, "I say 'carefully' because it can be done in a harmful way as well."Powerline corridors introduce edge habitat that can harm species that need large areas of unbroken forest. Sloppy construction techniques can cause erosion and introduce invasive plants. Poorly managed maintenance can result not in a rare ecosystem but in a defiled habitat filled with non-native species.

The difference in technique is minor, but the results are striking. Brian Connaughton, environmental team lead for VELCO, notes that wherever his organization uses integrated vegetation management techniques, rare plants seem to follow.

And that is a paradox for all power companies, notes Vermont Non-game and Natural History program botanist Bob Popp. Once they have created these rare and valuable ecosystems within their rights-of-way, power companies find themselves custodians of much more than just poles and wire.

Madeline Bodin is a writer living in Andover, Vermont.