In this file photo from December 2011, branches on the street side of a row of trees have been trimmed back as part of Westar Energy's program to keep trees out of power lines.

As crews work to clear trees and other vegetation from the path of power lines, some Lawrence residents are concerned not about what crews trim away, but what they’re adding.

The last time Lawrence resident Rob Matthews’ trees were being trimmed, he said he ran outside when he saw workers spraying something from a canister on his property. They informed him it was an herbicide and stopped spraying when asked, but as Matthews’ property comes due this year for another trimming, he wants to make sure that no pesticides are sprayed this time.

“It’s done as if they have a right to do it,” Matthews said. “I do think they have a right to trim out the trees whenever they start to endanger their lines, but I don’t think they have a right to poison the vegetation underneath.”

Anytime a tree is removed because of its proximity to power lines, crews will also spray the stump with an herbicide — a pesticide that is targeted to kill plant life — to stop the tree from growing back, according to Doug Lehmann, supervisor of vegetation management for Westar Energy. In addition, Lehmann said the herbicide would also be used when there is plant growth such as poison ivy on or around utility poles.

Lehmann said the crews use an herbicide called Garlon that is commonly available in hardware stores. The Garlon label states that it is a specialty herbicide for the control of woody plants and broadleaf weeds in non-crop areas, including rights-of-way such as power lines.

The label also states that Garlon is harmful to humans and animals if swallowed, and contact with skin, eyes or clothing should be avoided. Environmental hazards warn that the pesticide is toxic to fish, and should not be applied to areas where surface water is present or the water table is shallow.

Lehmann said the herbicide is most often applied to the stump of a removed tree, and if applied other places is done so very precisely, so as to not kill off other vegetation.

“If there is anything that’s sprayed it’s very targeted to only the stumps that we’re looking at, or say that poison ivy that we need to get back from a pole so that somebody can do maintenance on that pole,” Lehmann said.

However, Lehmann noted that the herbicide use is not the main aspect of the power line clearing in the city, where neighborhoods are done once every four years.

“Basically, it’s our reliability program,” Lehmann said. “We are actively trimming back trees, removing trees from the power lines to keep the power on, to keep them from getting up in there. The majority of our work is just trimming the trees back and we go on.”

Lehmann said property owners are always consulted prior to a tree being removed and that verbal permission to spray the stump is obtained at that time. Lehmann said in the case of weeds such as poison ivy growing on or around a utility pole, crews would not ask permission before spraying. When asked to estimate how often the herbicide is used without the permission of property owners, Lehmann said that it was “very rarely,” and estimated it was only a few times per year in the area.

Matthews said he has asked Westar to put information about the herbicide workers use in the notification material provided to property owners, which currently doesn’t mention its use. Matthews said the last time crews trimmed his trees, they just started spraying. Matthew said he thinks Westar should change its policy so that property owners are required to give permission before crews use a pesticide on their property.

“It think that’s entirely reasonable,” said Matthews, who lives in the Breezedale neighborhood. “It’s not just me; it’s my neighbors and the whole community that I care about.”

Lehmann said the companies contracted by Westar to do the work for Lawrence — Wright Tree Service and Asplundh Tree Expert Company — have been trimming trees in southeast Lawrence since January, with the majority of that work south of 15th Street and east of Iowa Street. He said if property owners don’t want the herbicide sprayed, they can contact Westar directly and let them know.