Recent tree spraying by a Rocky Mountain Power contractor in the community has had the Centerville City Council concerned. On Nov. 6 in a work session, they met with RMP representatives to discuss the issue.

In recent weeks Growth Solutions, a RMP contractor, has been spraying trees growing under or near power lines with a growth regulator, paclobutrazol (PBZ), to mitigate future power outages caused by trees. Growth Solutions sprayed trees on both city and private property. Although trees on city property were being sprayed, neither RMP nor the contractor notified the city.

When Councilmember Robyn Mecham noticed a technician spraying trees on 100 East on city property she asked him to stop because she was concerned about the proximity to a city well and past tree health issues in this area, she said. Following the encounter, city officials reached out to RMP, provided them with a map of all city water resources and asked them not to treat within 250 feet of any city water source. They also asked that they be notified in the future when Growth Solutions was doing the treatment in the city, something which should have been done this time but was overlooked, RMP senior utility forester Daniel Bridenstone said.

This growth regulator is “actually a beneficial treatment to trees,” Parks and Cemetery Director Bruce Cox told the city council he had since learned. “It does reduce the outer growth, but it improves the health of the root system and of the tree.” Also, according to the literature, PBZ is less toxic than toothpaste, caffeine and Windex, City Manager Brant Hanson said.

Although primarily RMP and its representatives are only allowed to treat trees that are in the public utility easement, they can go onto private property if branches from trees located there could impact the utility lines, Bridenstone said.

“Nothing contained in this section shall prevent Rocky Mountain Power when necessary, and with the approval of the owner of the property on which they may be located, from cutting down and removing any trees which overhang streets. Rocky Mountain Power shall make a reasonable good faith effort, including written notice to notify home owners of property with trees to be trimmed or adjacent to the trees to be trimmed at least 72 hours prior to doing the work,” the franchise agreement between Centerville and RMP says.

So, if a tree has an encroaching branch, then “the clearance for our lines is an average of 14 feet of clearance,” Bridenstone clarified.

Use of the growth regulator is preferred over pruning because “anytime a tree is trimmed, it has a hormonal response and the growth explodes afterwards,” he said.” I’m sure you’ve seen that, as you trim any tree, branches that just go on everywhere, and that growth can be 1,000 percent what the regular growth is.”

Treatment is generally done every three years. The amount of PMZ used depends on the species and age of the specific tree, Bridenstone said. Technicians undergo an extensive training program and must be certified by the Utah Department of Agriculture and Food.

Much of the discussion that evening centered on how affected residents are notified of the spraying. Months ahead of the scheduled spraying, residents receive a mailer informing them, Bridenstone said. They also notify residents a few weeks ahead of the spraying by knocking on doors or by leaving a door hanger if no one is home. The door hangers have information about the PBZ treatment and a number residents can call if they do not want their trees sprayed.

Although city council members made a case for the program to be opt out rather than opt in, to do that is actually quite difficult and costly, Bridenstone said, but was enthusiastic when Mecham suggested that with notification from RMP the city could put notices of upcoming treatments in its utility bills and on social media. 

“I think that’s absolutely something that we would love to do as a partnership,” he said. “We know where we’re going to be and what we’re going to be trimming and the areas we’re going to be in a year in advance – several years in advance. And so, we can absolutely set that up. We can have educational meetings. We can even meet with the citizens, whatever is needed to help the constituents feel more comfortable. We’re very open to doing that.”

RMP and its contractors want to work with the city and its residents, he said. “We do definitely want to make sure that the constituents understand what it is that they’re getting, and if they don’t want it, then by no means, we don’t want to force them to do that, because it, of course, costs us money to do that and, if we can just educate them and help them feel at ease, I’m happy to do that.”