Forest Service seeks public comment on herbicide application in Bighorn National Forest

GREYBULL - The Bighorn National Forest Invasive and Other Select Plant Management Project is a recent endeavor following in the footsteps of similar projects in Sheridan and Johnson County, as well as in the Jackson area. The main goal of the project is to control the population of invasive annual grasses, namely medusahead (Taeniatherum capu-medusae) and ventenata (Ventenata dubia).

On July 27 Bighorn National Forest officials held a public meeting for their Bighorn National Forest Invasive and Other Select Plant Management Project. The meeting was held at the Big Horn County Weed and Pest Office outside of Greybull, with project lead Acting Resource Staff Officer Thad Berrett and Forest Supervisor Andrew Johnson presenting information about the project and looking to answer questions from the public.

An additional action proposed for the document also seeks to reconstruct the mountain big sagebrush control plan currently in place. Sagebrush has consistently been removed to allow the growth of understory plants for decades. The project lists this as a "resource protection measure," ensuring that there will be grasses for grazing animals.

While action is currently taking place in an effort to reduce the prevalence of these invasive plants as well as mountain big sagebrush, the new proposal would increase efforts to eradicate the problem through aerial application of herbicides and an increased treatment area.

In Tuesday's public meeting, the purpose for the project was described as follows:

"There is an urgent need to add the aerial treatment to the existing tools. These two species (medusahead and ventenata) in Sheridan and Johnson counties were the first known populations in the Northern Great Plains ecoregion and were first discovered there in 2017. Sheridan and Johnson counties have made treatment a priority, and Big Horn and Washakie counties have made surveillance a priority. Sheridan County has treated over 28,000 acres of ventenata and medusahead in an area adjacent to the Bighorn National Forest in 2020. The aerial application of these herbicide tools is needed so that Bighorn National Forest can redeem its shared stewardship responsibility in the connected landscape."

The Bighorn National Forest Invasive and Other Select Plant Management Project lists three "Alternatives," of which one must be approved and put into place.

Alternative 1 – No Action: The current weed management program would continue. Herbicides would be applied using ground-based methods; aerial application would not be used. Current sagebrush treatments in sagebrush grasslands include prescribed fire, mechanical, and in some instances, ground-based herbicide use. The current sagebrush treatment is approved through site-specific project evaluation and Alternative 1 would not provide treatment of sagebrush outside of those areas already approved for treatment which is within about 68,000 acres of sagebrush habitat. This option is estimated to treat 3,110 acres of invasive plant species and 800 acres of sagebrush. Some invasive plant species may be eradicated and some prevented from spreading, but overall, acres of infestation are likely to increase. Invasive annual grass infestations would be more likely to spread. Use of any herbicide available under this alternative could result in damage or mortality to native vegetation; however, resource protection measures, label restrictions, and selectivity of some herbicides would minimize those adverse effects.

Alternative 2 – Proposed Action: Herbicides would be applied using ground-based methods as well as controlled aerial application. Implementation of treatments for mountain big sagebrush would increase to approximately 163,000 acres of sagebrush habitat using existing treatment methods. Alternative 2 is estimated to treat 5,310 acres of invasive plants and 5,100 acres of sagebrush. Invasive annual grass control with herbicide use through aerial application would have both a direct and indirect benefit to native vegetation communities. All herbicides considered could result in damage or mortality to native plants that are immediately adjacent to or interspersed with target invasive plant species, however, those adverse effects would be reduced by implementing resource protection measures and selecting appropriate herbicide application method, rate, timing and surfactant.

Alternative 3 – No Aerial Application of Herbicides: This alternative is similar to Alternative 2, except the application of herbicides using aerial platforms would not be allowed for either invasive species or mountain big sagebrush. Up to 10,240 acres of invasive species could be treated, as well as 2,400 acres of sagebrush. Lack of aerial application herbicide treatments would limit the Forest Service's opportunities to work with stakeholders and surrounding landowners, which could lead to a spread of invasive plant species on National Forest Service land. However, if close to 10,000 acres of invasive plant species were treated annually using ground-based herbicide methods, this would help to reduce large infestations of invasive annual grasses and other invasive plant species.

"Personally I think we need the tool," said Cliff Winters, Big Horn County Weed and Pest Supervisor of aerial herbicide application. Project supervisor Berrett went on to explain that drones, fixed-wing planes and helicopters were all viable options for application under the project plan. The project also outlines precautions for avoiding herbicide drifting, waterways and sensitive plants and animals.

Audience members questioned the possibility of ATV and vehicle checkpoints to inspect for invasive species, which is outlined as a possibility within the project plan. "Right now there is no charge or inspection foreseen," said Berrett.

Forest Supervisor Johnson explained that while there are not currently any plans to introduce inspections, it is a viable tool that may need to be implemented in the future. "Contractors and roadwork crews are required to have a vehicle inspection," he pointed out. "If we get to the point where we need to use them, we will."

The public also brought up many questions about the types of herbicides being used, as well as their effectiveness and approval from the Environmental Protection Agency (EPA). "All herbicides in the document have been approved by the EPA. As new tools and options come forward, they will have to be studied and approved by the team to be added to the treatment," Berrett said.

Currently, Berrett listed Rejuvra as a commonly used herbicide for annual grasses and 2,4-D for sagebrush. According to environmentalscience.bayer.us, Rejuvra provides "long-lasting control of invasive annual grass and broadleaf weed species including cheatgrass, medusahead, ventenata and red brome. With the use of Rejuvra (indaziflam) herbicide, it is possible to stop invasive annual grasses by preventing germination of their seeds and depleting the weed seed bank."

Berrett noted the herbicide's effectiveness, saying that the herbicide binds to the top layer of soil and only targets annual grasses, leaving perennials unaffected. He said that it has remained effective for three to five years on medusahead and ventenata.

The herbicide 2,4-D "Kills broadleaf weeds but not most grasses. 2,4-D kills plants by causing the cells in the tissues that carry water and nutrients to divide and grow without stopping," according to the National Pesticide Information Center.

All herbicides could potentially harm native plants and animals, waterways, and people if not properly controlled.

When asked if pesticides could be applied aerially to control grasshopper and Mormon cricket populations, Berrett said that pesticides are not currently part of the project plan.

Comments on the project must be submitted by Aug. 9. Only individuals and organizations who submit timely and specific written comments regarding the proposed project during the public comment period established are eligible to file an objection. Written comments can be submitted to [email protected] with "Invasive and Other Select Plant Management Project DEIS" in the subject line, by regular mail to Forest Supervisor, Bighorn National Forest, 2013 Eastside Second Street, Sheridan, Wyoming 82801, or faxed to 307-674-2668. Comments can also be hand-delivered Monday-Friday between 8 a.m. and 4:30 p.m. to the above address.

"We thank you for any input you have. Comments are valuable, but it's not a popularity contest and it's not a vote," said Johnson. He noted that the Bighorn National Forest officials will ultimately make their own decision, but public comments bring insight and perspective.

To view the project document with full details, visit http://www.fs.usda.gov/project/?project=57457.