Tree growth retardants (TGRs), which control growth in a tree's crown, help utilities extend trim cycles, reduce biomass and improve tree aesthetics. At Energy-United, Lexington, North Carolina, U.S., this tool helped: - Extend trim cycles by 100% - Decrease branch growth by 50% - Substantially reduce biomass - Save thousands of dollars yearly.

Since 1990, EnergyUnited has used TGRs to effectively manage the growth of fast-growing species such as maple, oak, sweetgum and poplar under power lines on landowners' property throughout our service area, which encompasses parts of 19 counties.

In particular, we've been able to decrease the growth of maple trees. Untreated maples typically grow 4 ft to 7 ft (1.2 m to 2.1 m) each year. TGRs reduced their growth to 2 ft (0.6 m) per year. Overall, our cycle-busters require trimming every three years, but with TGRs, we've extended the cycle to six years.

By not sending a crew to trim as often, we can manage more trees annually and address other rights-of-way that need work. This program improves the reliability of our system, which should help us retain customers in a deregulated environment.

TGRs also help reduce biomass and increase savings. By reducing growth, we take less out of the tree, cut down on trimming frequency and can trim the tree more quickly. We also decrease clean-up time because we have fewer chips and less biomass to manage, which in turn decreases our removal time.

"We save at least US$100 per tree per year by combining TGRs with trimming," says Richard Fay, vice president of engineering for the co-op. "Multiplied by the approximately 450 trees we treat annually, this equals US$45,000 per year. The more trees we treat, the larger our savings."

While our TGR results may be impressive, they didn't occur overnight. We used TGRs for several years before we saw significant cost savings. With the recent positive TGR research on conifers, we plan to begin using the technology to also control growth of pine trees.

Currently, one applicator treats 450 to 500 trees each year along 9800 distribution miles (15,768 km). Using the soil-injection method, the applicator applies Profile 2SC tree-growth regulator, manufactured by Dow AgroSciences LLC, just prior to bud break in spring.

Communicating with Customers Before applying TGRs, we obtain permission from each landowner. First, we survey and target the trees in our service area for TGR treatment the next year. Then, we notify property owners in person to explain the program and obtain permission to treat with TGRs. We explain what a TGR is and promote the need for reduced trimming, which helps maintain the tree's natural shape and reduces the number of times we visit customers' properties to trim. Our notification program has led to a nearly 100% approval rate. In our seven years of TGR use, we've only had three refusals.

If customers request a handout during notification, we offer a brochure from Dow AgroSciences, which answers most of the frequently asked TGR questions. We also offer handouts at our local offices covering all aspects of the vegetation management program.

To help our notification efforts, we include articles about our TGR program in a newsletter mailed to our customers. According to Sharon Ervin, EnergyUnited's manager of communications, the articles help create awareness of the co-op's vegetation management program. "Providing information to consumers equates to positive customer relations, a necessity for utilities competing for customers," Ervin explains. "The more information we convey about our operation, the better. It helps us create an identity and establish rapport with the public."

Jimmy Brown, the director of R/W at EnergyUnited, oversees the utility's vegetation management program. He joined the co-op, formerly Davidson EMC, in 1977.