Vegetation managers don’t have to take the good with the bad when it comes to managing rights-of-way (ROW). While using nonselective management methods may be effective in taking out the incompatible trees and brush that threaten system reliability, they could eliminate many compatible plant species that may be present.
A better alternative involves integrated vegetation management (IVM) using selective herbicides to actively manage ROW corridors. Taking a more targeted approach opens the door to a suite of potential benefits, including:
· An improvement in environmental stewardship by implementing selective control methods as part of an IVM approach, which chooses to remove incompatible species with a methodology resulting in minimal impact to the residual species.
· Enhanced ROW habitat and biodiversity proven by more than 60 years of industry research as part of the Pennsylvania State Gamelands 33 and Greenlane Research & Development projects.
· Increased freedom to operate on more sensitive areas, where a friendlier management approach and improvement in habitat can help open doors.
This list of opportunities helped spur Georgia Power Company to begin looking at a more selective management approach for its ROW program. Matt Goff and Matt Chambers, both vegetation managers, forestry & right-of-way services, with Georgia Power Company, said herbicides were already a vital component of Georgia Power’s ROW maintenance program. It was just a matter of switching to a selective mix and more targeted application methods.
“Herbicides provide us with a simpler means to gain effective brush control while incurring less costs than other methods,” Goff says. “But as we endeavored to evolve our IVM approach, we also saw room for improvement. We were eager to work with Corteva Agriscience to establish a pilot program aimed at realizing he potential benefits of brush control using selective herbicides.”
Rights-of-way follow a predictable pattern of vegetation growth. Using selective practices to eliminate incompatible species with minimal to no effect on grasses, forbs and other herbaceous plants encourages a takeover by these early successional plant species. For Georgia Power, those species include many native grasses and succulents. None of these species cause any concerns over height, so they can be allowed to thrive — serving to suppress tree seedlings and increase soil stabilization.
“We were especially interested in the potential biological and ecological impacts of brush control using selective herbicides,” Goff says. “We saw opportunity to align our vegetation management practices toward preserving our rights-of-way in the early successional stage of vegetative growth.”
Chambers agrees and saw a means to use desirable ground cover to specifically help suppress pine species.
“There are numerous timber-stands in our area,” Chambers says. “That means whenever we sprayed our traditional, nonselective treatment, you’d expect to see lots of pine seedlings filling in any bare space that’s created. While the pines were initially controlled by the treatment — without any desirable ground cover to hold them off — they many times would come right back.”
A new focus on selectivity
To help Georgia Power meet its goals, Corteva Agriscience recommended a selective herbicide mix. It consists of Vastlan® herbicide at 2.25% combined with Milestone® herbicide at 0.33%, along with a surfactant at 1%. Vastlan provides control on a broad spectrum of conifers and hardwood species like oaks, sweetgum, maple and hickory, and Milestone enhances control on pines and select hardwood species, with added invasive weed control.
Before any applications were made, Georgia Power worked with its contractors to ensure the contractors properly trained its applicators in using this new mix, as selective brush control results are closely tied to using proper application techniques. Training focused on the importance of adequate coverage because, with selective herbicides, the goal is to cover the crown of the target species as well as at least 75% of the terminal growing points.
The pilot program began with the 2018 foliar spray season. That year, low-volume foliar applications using the new selective herbicide mix were made to 15,000 acres of Georgia Power transmission lines and 3,000 miles of distribution lines. The focus turned more to distribution lines in 2019 with approximately 15,000 miles treated, and Georgia Power plans to spray approximately 13,000 in 2020.
Optimistic observations and positive early results
When using selective brush control treatments, it’s important to understand how control will play out over time. In comparison, after a nonselective treatment is made, there is more evident brown-out and results tend to be measured more immediately. With selective treatments, there is certainly visible control on many species that occurs quickly. But then one must also account for the benefits of having more grass and other desirables, creating a biological barrier against incompatible brush re-sprouting over time. It’s a several year process whereby the right-of-way transitions to an easier-to-maintain, early successional plant state.
Although the test plots won’t show more definitive control results for Georgia Power until later this year, there were some initial advantages that have been realized since implementing selective brush control treatments.
“Overall, it’s a little bit of learning as we go, but we’re optimistic with what we’ve seen so far,” Goff says. “We don’t expect to get a full measure of what the control rates are on the initial rights-of-way we treated until after this growing season, especially with hardwood species.”
On some species, the control has already been evident. “We’ve seen excellent control on pine species,” Chambers says. “And in our field observations, we are definitely seeing where grass will help suppress the further germination of the conifers. In areas we’ve been able to maintain the grasses, it’s had a pretty striking affect.”
The selectivity has also resulted in better overall customer interactions and reduced scrutiny from landowners around treated areas.
While continuing to monitor the overall control results of its initial pilot program, Georgia Power is working with Corteva Agriscience to quantify the biological benefits it expects in the form of reduced tree seedlings reappearing as a result of the increased presence of desirable species.
These initial successes combined with the expected longer-term benefits have kept the program in place, allowing Georgia Power to further leverage the advantages this approach produces for its ROW maintenance program.
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™ ® Trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. 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. State restrictions on the sale and use of Milestone apply. Consult the label before purchase or use for full details. Vastlan is 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.