Vegetation Management

The rising humidity from the late-May rain shower that morning clung heavy in the air as she sloshed through the creek bed in a rural neighborhood served by United outside of Cleburne.

Tracy Barefoot, a consulting utility forester with ACRT: Independent Vegetation Management, carefully hiked up and down the rough, muddy terrain until coming to a recently cleared area where United’s electrical infrastructure stood. Her company provides vegetation management services for United and other utilities. Keeping vegetation out of the lines improves reliability for United members.

As difficult as passage to the worksite was, Barefoot said she was exactly in her element.

“I love my job,” she said. “In fact, the lady who had it before me said ‘This job is made for you.’ She said, ‘I told them they would be very remiss if they didn’t hire you for this job.’”

In the clearing, 40-foot trees towered on either side of the lines. Branches from elms and cottonwoods lay on the ground from the recent activity, and the sun shone brightly through the recently cleared area.

As Barefoot arrived at the site, a crew of about 20 trimmers from The Arbor Experts either waited to assist on the ground or fastened their harnesses before winching themselves high into the air. Saws buzzed and branches fell quickly until the arborists had the untamed wilderness expertly trimmed back to mitigate future growth into the lines.

“We have some areas that are better, and some that are worse, but this area was definitely one of the ‘worse’ ones,” she said the next day. “This crew is definitely amazing. They probably got about 350 to 450 feet done yesterday, which is a big accomplishment trimming manually when they’re climbing like that in such dense conditions. They covered a lot of ground. They just fly.”

In 2018, United began an enhanced effort to improve reliability through better vegetation management, said Quentin Howard, senior vice president of system engineering. The 2018 Integrated Vegetation Management (IVM) effort replaced an earlier plan that relied on line crews trimming certain circuits chosen every year as well as areas considered “hotspots” for outages.

The new IVM employs arborists with expertise on tree trimming to minimize regrowth, he said. ACRT teams also encouraged United to employ other tools, such as herbicides and growth inhibitors, to extend the lifetime of the trimming, reducing costs in the long run.

“In 2018, we converted from an old right-of-way program, which was basically maps and mechanical trimmers, to a true program where you employ herbicides and sometimes remove trees,” he said. “Prior to 2018, we weren’t using any herbicides or tree-growth inhibitors, and we weren’t doing any tree removal. We were trimming eight to 10 feet from the lines, and it was truly ‘lop it off.’  By bringing in arbor experts who specialize in this, we found there’s a better way to cut those trees to prevent them from growing straight back up into lines like it does when you just ‘lop it off.’”

Five years after launching the IVM, Howard said the more methodical approach has helped improve reliability in many areas. Part of that improvement involves the planning arborists do. For example, after cutting in a forested area, vegetation management teams will return to the site where the canopy has been removed. After some time has passed, they return to the recently cut area and begin treating the new growth, which is growing rapidly to fill in where taller foliage was removed, with herbicides or trimming to extend the remediation time for the area.

The trimming service can mean marked improvements for reliability, he said. For instance, two circuits on the Burleson substation had 14 vegetation-related outages that affected 202 members between May 2022 and February 2023. Following the management process, those same circuits experienced only three vegetation-related outages affecting eight members between February and May 2023.

History has also taught officials at the co-op that cutting strategies must vary from year to year depending on rainfall, he said.  And each spring, Mother Nature shows arborists where areas may need more attention.

“Each one of these storms is different, and each one challenges us in a different way,” Howard said. “With this last big storm in May, we had a lot of lightning, and we had a lot of straight-line winds. I think we were looking at 70 mile-per-hour winds across much of the territory, and those are brutal conditions. On top of that, we had a lot of tree damage from trees that died during Winter Storm Uri in 2021, and they showed up because of the high winds. The high amount of rain this year also caused many trees to just fall down in those winds because the ground was so waterlogged.”

The new vegetation process will continue adapting and modifying strategies to bring even greater reliability as the program continues.

“You’re never going to hold Mother Nature back,” he said. “However, we believe we’re still on the right track, and the overall vegetation management program is extending the time between cutting cycles and reducing the overall future cost when the areas are revisited. While the results of the new emphasis and strategy we’ve developed within the IVM program today may not always be visible, the data show we continue momentum—which will make our continuing investment in vegetation management more manageable in the future and provide our distribution system greater resistance to weather effects.”      

For more information on the program, visit www.ucs.net/vegetation-management-program.