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Alan Fazio remembers what clearing right-of-way was like before his co-op began integrated vegetation management, or IVM.
“We spent 90 percent of our resources running down hot spots,” says Fazio, vice president of engineering and operations at Lake Region Electric Cooperative in Pelican Rapids, Minnesota. “Maybe 10 percent of it was dealing with planned issues.”
Today, through an IVM program that uses plant sampling and data analytics to guide multiyear cycles of clearing and maintenance, Lake Region Electric has reversed the equation.
“After we got into the second cycle, we probably spent 90 percent on planned issues and 10 percent on hot spots,” Fazio says.
The shift from responding to vegetation problems to proactively preventing them can have big rewards. A successful IVM program can mean reduced costs, fewer outages, and better member relations. Since implementing IVM 10 years ago, Lake Region Electric has cut its annual vegetation control costs almost in half, Fazio says, from about $2 million a year to between $1.2 million and $600,000, depending on where the co-op is in its maintenance cycle.
IVM combines forestry, horticulture, chemistry, and computing to cut costs and boost system reliability through the more efficient and environmentally sound control of trees and underbrush around lines. A successful program gives utilities a clear view of what’s growing up and around lines, where the potential trouble spots are, how they can best be dealt with, and which low-lying plant species should be encouraged.
While the tools of traditional vegetation management have been chainsaws, sprayers, and other old-school implements, IVM also takes advantage of some of the latest technology. Several companies—including ACRT, AgTerra Technologies, and Clearion—offer IVM software and services to develop management plans, calculate costs, and track progress.
Lake Region Electric employs ACRT’s Arborcision, which uses on-the-ground sampling and analytical software to find the most efficient approach to managing growth in a utility’s rights-of-way.
The company begins by taking samples of vegetation along power lines based on a statistical model. That information is combined with data about the co-op’s annual budget for brush and tree clearing and how many miles it clears annually, then it’s plugged into an algorithm.
“What it spits out is a game plan for the utility,” says John Wasmer, ACRT executive vice president of revenue. “It prioritizes circuits. Say a co-op has 3,000 miles of line, and in those 3,000 miles, there’s a hundred circuits. The co-op can ask what circuits need trimming, and it will say, if you trim circuit A, it will be $50,000 less if you trim it this year.”
ACRT usually audits a system every two years, since growth rates and even types of vegetation can change depending on weather conditions.
“You could have two years of a wet season or two years of a dry season,” Wasmer says. “That can really swing your vegetation assessment dramatically.”
The results have changed the work load of the tree-trimming crews, who are now able to tackle most species before they become a significant problem.
“It’s a rarity for our crews to spend much time running a chainsaw,” Fazio says. “We are more precise on where we trim and when we trim.”
But the most meaningful metric of success, he adds, is found in system reliability.
“We’re keeping our outage numbers down, which is the end result we really want.”
Clearing the way for reliability
High-resolution mapping has enabled co-ops to take full advantage of IVM.
Crawford Electric Cooperative, based in Bourbon, Missouri, uses ESRI software to track vegetation on its 3,000 miles of line. The co-op serves mostly rural country southwest of St. Louis that includes rolling hills and, farther south, rugged, more heavily forested terrain with an active logging industry. Oak and hickory trees dominate the wooded areas.
Map overlays allow the co-op to track when every circuit was last checked and cleared for troublesome trees or other vegetation, along with the methods used to check growth and encourage alternative vegetation. The goal, says Right-of-Way Superintendent Terry Gordon, is to “promote desirable, stable, low-growing plant communities that will resist invasion by tall-growing tree species.”
The cooperative depends on the expertise of its professionally trained staff as it determines where selective cutting or limited herbicide use is necessary and what types of replacement vegetation should be encouraged. Gordon has a degree in forestry, while another staff member is an expert in wildlife management and the local wildflowers that make good low-lying cover.
The co-op’s IVM plan also integrates methods for managing plant growth.
“Every seven to nine years, we apply mechanical methods. Then two years later, we apply selective herbicide to the rural right-of-way,” Gordon says. “All of our system has been managed through at least two re-entry cycles.”
Co-op field personnel, including tree-trimming crews, have access to the geographic information system (GIS) software on iPads that allows them to pinpoint specific trees within rights-of-way, along with other key data.
“They can pull up the aerial photos, and they click on the various accounts, and it gives them gate codes and special information about what else might be waiting for them there,” Gordon says. “It just saves them a lot of time and helps to keep costs down.”
The land under and immediately adjacent to the co-op’s lines had become so overgrown when Crawford Electric first began IVM 20 years ago that the initial “reclamation stage” was expensive, up to $5,900 per mile, Gordon says. The task involved reclaiming “our 30-foot-wide right-of-way, floor to sky,” he adds. “This included the removal of yard trees that were previously trimmed.”
Two growing seasons later, the co-op applied selective herbicides using low-volume applications that targeted what Gordon described as “prolific stump sprouters,” which were mostly oak and hickory. Since then, Crawford Electric has been in its regular maintenance cycle.
The transformation in the cooperative’s system since it began IVM is revealed through aerial photography.
“Twenty, 30 years ago, you can’t even see our grid,” Gordon says. “Today, you can actually see what we’re doing.”
Since the co-op moved into regular IVM cycles, costs have stayed reasonable, often below the rate of inflation, he adds, despite the wages of tree-trimming crews almost doubling during that time.
Member relations have also improved thanks to IVM. Trimming or cutting down trees around a member’s home is often a touchy situation. But being able to explain to them exactly why the action is being taken at that time and how the cooperative is taking a long-term, scientifically based, environmentally sensitive approach has helped relieve members’ concerns.
“Members grasp and appreciate a proactive approach to how our grid is managed,” Gordon says. “It resonates with most members when you explain parts of the plan to them.”
The cooperative follows the guidelines of the Arbor Day Foundation’s Tree Line USA program, which encourages co-ops and other power utilities to make wise and limited use of herbicides and to plant new trees safely out of the way of power lines to replace those that must be cut down.
“When a yard tree is removed, we do have tree replacement vouchers, which are basically gift certificates to one of the six participating local nurseries,” Gordon explains. “We also offer stump grinding for live yard trees that we remove.”
That effort may not be a required part of any IVM program, but Gordon notes it can both build goodwill with members while demonstrating that the overall goal of the program is not simply to chop and cut but to manage vegetation responsibly.