Back to the Future of Vegetation Management

Men looking at a utility ROW

Vegetation management is a constant process for utility companies. The development of incompatible plant communities in right-of-way (ROW) corridors can lead to accessibility issues, service interruptions, wildfires and the destruction of native wildlife habitat. Many vegetation managers struggle to keep up with maintenance demands because of budget restrictions and a shortage of skilled workers. With tens of thousands of miles of utility rights-of-way stretching across the country, it can be easy for vegetation managers to settle for a quick solution or only address short-term reliability needs. But research has shown that some strategies can be more costly than others.

Oklahoma Gas & Electric (OG&E) has provided electrical power to customers throughout Oklahoma and western Arkansas since 1902. Each year, the company keeps 5,800 miles of transmission corridors free of threats to utility service reliability and the surrounding environment. A key component of this includes controlling incompatible vegetation. These efforts help ensure utility service is safely provided to nearly 860,000 customers throughout the company’s 30,000 square-mile service territory. The process requires consistent analysis and often reveals opportunities for improvement.

“One of the things we do very well is assessing what’s working, identifying what’s not working and figuring out how we can change that,” says Shawn Huff, who has worked as supervisor of Vegetation Management for Transmission and Facilities with OG&E since January 2019. “Overall, our goal is to provide safe and reliable power.”

OG&E previously relied on mechanical mowing and trimming strategies to keep tree species — like locust, elm, hickory and sweetgum — from interfering with power lines and jeopardizing electrical transmission reliability. But a variety of unfortunate events soon revealed the downfalls of this strategy to Oklahoma’s oldest and largest investor-owned electric utility.

One year, when a tornado tore through northern Oklahoma, it took nearly a week to mow access paths large enough for service providers to reach the damaged wires and towers. Examiners also struggled to conduct aerial inspections over thousands of transmission and distribution line miles as the growth of woody brush had made it difficult to see power lines and utility components. In another part of the state, vegetation found growing inside of an OG&E tower had caused corrosive damage. The company knew it was time to rethink its vegetation management strategy.

Improving Efficacy

To fight stubborn species and aid in the development of native plant communities, OG&E began using selective herbicide treatments in the early 1990s. After witnessing how herbicide treatments expedited the restablishment of native grasses, OG&E chose to dedicate nearly one-third of its vegetation management program budget to herbicide applications. Considering the noteworthy results, the company had even formed plans to use herbicides nearly exclusively in the future. However, in the years that followed, OG&E slowly reverted back to mechanical mowing as its chief strategy for vegetation control.

As the cost of mowing maintenance increased over time, budget for herbicide treatments was reallocated. Now, more than two decades later, the company is once again looking to increase the effectiveness and cost efficiency of its vegetation management program by using an Integrated Vegetation Management (IVM) strategy featuring selective herbicide applications.

Familiar Territory

Mechanical mowing can provide temporary relief from incompatible vegetation, but it often stimulates regrowth, which can increase stem densities over time. Recent research studies have shown that mowing alone can result in maintenance costs that nearly triple costs associated with an IVM-based program. This gap increases as selective herbicides work to eliminate only targeted plants. Excited by the opportunity to do more with less, OG&E is now working to integrate herbicide treatments as a long-term solution for vegetation management.

“Selective herbicide applications aren’t just sustainable – they’re scalable,” Huff says. “When you compare trimming a tree and having it grow into power lines in three years to spraying a tree and not having it grow anymore, the results aren’t even comparable.”

With thousands of miles of transmission corridors to maintain, Huff is interested in strategies that allow his teams to make the best use of available resources.

“Budgets are going to always be tight,” Huff says. “That’s why we want to be as effective as possible with the dollars we’re given.”

Environmental Considerations

The high cost of mowing practices can be as troubling as their environmental impact. Using mechanical mowing exclusively to maintain incompatible plant species on utility rights-of-way can cause damage to native plant communities and surrounding wildlife. That’s why using herbicides instead of mowing provides a significant advantage to OG&E in its fight against one of the region’s most prevalent invasive species.

“We have a very large problem with johnsongrass,” Huff says. “But we can use herbicides to remove it without damaging the landscape and wildflowers.”

As johnsongrass can outcompete native plants and grasses with ease, its presence poses a significant threat to wildlife. That’s why OG&E works to protect wildflower species that support pollinators, like native bees, honey bees and various butterflies. Selective herbicide applications provide an effective and cost-efficient solution for these environmental issues.

“With herbicides, we can achieve our goals and still have a positive impact on wildlife species like pollinators,” Huff says. “We’re saving money from mowing, but it’s resulting in a net benefit to the environment as well.”

Taking the Right Steps

The transmission team for OG&E started using high-volume herbicide applications this past foliar season. Dormant-stem treatments and basal applications have also been used this winter to control incompatible plant species throughout the company’s ROW corridors. Huff ensures his teams are using the right solutions to achieve these desired results by working with Scott Wright, a vegetation management specialist with Corteva Agriscience.

Wright’s industry knowledge and educated recommendations have led to the company using cutting-edge products like TerraVue™ and Vastlan® herbicides. The tank mixes he has prescribed provide vital support to chemical limb-trimming applications in the field. 

“We chose a tank mix of TerraVue and Vastlan for OG&E because it supported the company’s long-term objectives and allowed applicators to use a single spray tank for both limb trimming and brush work on the floor,” Wright says. “This allows OG&E to complete both applications while staying within specified rate ranges and reducing the need for multiple trips.”

For OG&E and other utility companies across the country, IVM programs featuring selective herbicide applications and supplemental mowing or trimming can translate to cost savings, enhanced worksite safety and a variety of environmental benefits.

“Vegetation management is an ongoing responsibility for utility companies,” Wright says. “If a program can fully commit to a herbicide-based approach for 20 years, there’s no telling how much time and money it will save.”

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™ ® Trademarks of Corteva Agriscience and its affiliated companies. When treating areas in and around roadside or utility rights-of-way that are or will be grazed, hayed or planted to forage, important label precautions apply regarding harvesting hay from treated sites, using manure from animals grazing on treated areas or rotating the treated area to sensitive crops. See the product label for details. TerraVue and Vastlan® are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.

 

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