Duke Energy suspends use of chemical product that stunts tree growth

In response to public outcry, Duke Energy said Wednesday that it has temporarily stopped using a chemical product that keeps limbs away from power lines by stunting tree growth.

Crews have canvassed Dilworth, Sedgefield and other tree-lined neighborhoods in recent weeks, injecting the soil near hundreds of trees with Cambistat, a product that regulates the size of limbs.

The move angered some homeowners and others who said they were blindsided and worried the chemicals would leach into groundwater and harm small children and pets.

Complaints grew louder on social media after an Observer report last week detailed the complaints.

Duke and the Minnesota-based manufacturer, Rainbow Treecare, maintain that Cambistat is safe. They insist that it actually makes trees healthier.

Duke spokeswoman Paige Layne said the utility failed to adequately forewarn customers and inform them about why it planned to evaluate the use of Cambistat.

“We want to figure it out,” Layne said.

Critics said they were relieved that Duke listened to their concerns.

City Council member John Autry had asked a city attorney to look into whether Duke was legally entitled to inject chemicals in the ground to protect power lines. He said he has doubts about whether Cambistat can be used safely.

“I appreciate Duke Energy being sensitive to the public concerns,” Autry said.

Charlotte has one of the thickest urban forests in the country, increasing property values and reducing energy costs for homeowners.

But long tree limbs undercut Duke’s ability to deliver uninterrupted service to customers. The company has been criticized for trimming trees that threaten power lines.

To lower costs and reduce complaints, Duke hired Rainbow Treecare to inject Cambistat in Charlotte, Greensboro and Durham.

In Charlotte, workers planned to treat trees in the Dilworth, Myers Park, Sedgefield and Plaza Midwood neighborhoods and along Park Road in south Charlotte.

Workers put Cambistat into soil at the tree’s base, where it is absorbed into the roots. Cambistat slows branch growth by 40 to 70 percent by altering a tree’s hormones, Duke and Rainbow Treecare said.

City administrators raised no objections last month when Duke alerted them they wanted to use the product on trees in the public right of way.

Workers from Rainbow Treecare had to ask homeowners for permission to inject Cambistat in private yards. Some residents complained that they were not told sooner that they could opt out.

About 300 trees on private and public lands were treated before the effort was halted, Layne said.

Layne defended Cambistat, saying it has been on the market for years. The product has been approved by the federal Environmental Protection Agency, she said.

Questions about safety arose in part because Duke distributed literature that was incomplete, Layne said. She also noted that workers did not have badges that clearly specified that their labor was authorized by Duke.

Mary Lou Buck, a board member for the Freedom Park Neighborhood Association, said she is pleased Duke is suspending the use of Cambistat.

Buck said her neighbors had concerns despite assurances from Duke. Even some residents who defended Cambistat acknowledged they wouldn’t allow children and pets near trees immediately after an injection, she said.

“There were answers to some questions, but there were not answers to all of them,” Buck said.

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