Integrated Vegetation Management for Roadsides
Integrated Roadside Vegetation Management (IRVM) can be considered as quality management for roadsides. It is a decision-making process that considers a variety of tools to manage vegetation in an economically and environmentally-sound manner.
Vegetation along roadsides is managed for a number of reasons including maintaining visibility for drivers, reducing water and debris on the roadway, protecting longevity of the road surface, reducing erosion control, minimizing fire danger, and providing sustainable vegetation.
The Idaho Transportation Department IRVM program is a coordinated decision-making and action process that uses the most appropriate pest-control methods and strategies to meet the agency’s programmatic management objectives.
Our IRVM program relies on consideration of all methods for controlling and maintaining vegetation. Developing a successful IRVM program means one must consider all management practices, determine the desired result, and examine the facts.
Arbitrarily ignoring or discounting a pest control method upsets the balance of an integrated pest management approach. Management tools such as mowing, mapping invasive populations, using beneficial insects, herbicide applications, revegetation efforts, and plant selection are all appropriate and cost-effective depending on the site, funds available and management goals.
ITD objectives of a successful Integrated Roadside Vegetation Management program include providing safe and reliable transportation, maintaining infrastructure investments, operating within budget and personnel limitations, and minimizing environmental impacts.
Ultimately, the goal is to make informed decisions on how to best manage roadside vegetation and achieve effective results. Costs can be managed more effectively when they are prioritized within an IRVM program. Prioritizing ensures that the most effective activities take precedence first.
Elements of ITD’s Integrated Roadside Vegetation Management
Mowing vs. Herbicide Use
Case Study – I-84 Corridor Project:
In 2004-05, fuel break development language was added to the SAFETEA-LU (Transportation Bill) to secure future funding for follow-up fuels projects, the Wildfire Impact Reduction Coalition (WWIRC) was formed and goals were established to encourage fuel breaks on roadsides, wildland/urban interface areas and for protection of critical habitat areas; Bureau of Land Management (BLM) implemented numerous small research fuel management projects using Plateau herbicide, BASF secured funding for monitoring and establishing additional field trials, and Idaho Transportation Department (ITD) completed evaluations of the I-84 fuel treatment options and vegetation types in preparation for implementing this demonstration project.
The purpose of this project is to utilize the I-84 corridor east of Boise as a demonstration fuel break to reduce fire frequency and intensity. Continuous treatment is needed within the defined areas for proper evaluation of the fuel break demonstration.
There is a high incident of wildfires across this stretch of highway, with a map available of wildfire history. After vegetation treatments are implemented, natural wildfire behavior across treated versus non-treated areas will be monitored through data collection and observation. New wildfire behavior in treated areas will be compared to recent and historic fire behavior. The results of this study will be published in a brochure as well as posted on the WWIRC resources website as a model for others to learn from and assist them in establishing future roadside fuel breaks.
The I-84 corridor contains intermixed areas of solid cheatgrass stands with areas of native vegetation infested with cheatgrass. The project area (fence-to-fence) includes ITD right-of-way, state and private lands, as well as BLM land. The maximum area to be treated is approximately 2,500 acres. Dependent on the specific area (cheatgrass load, slope, vegetation type, burn history, etc.), treatments would include mechanical (mowing), herbicide using Plateau and other approved herbicides, mechanical seeding and revegetation, and fuels treatments other than herbicide.
Agency contributions included:
FHWA contributing $25,000 for Plateau purchase, application, monitoring, etc.
Results of the 2005-06 treatments include Plateau treated in the burned and unburned areas resulted in 70 percent cheatgrass control achieved, non-burn areas containing a heavy thatch layer resulted in poor control of cheatgrass (less than 35 percent) with only visual stunting; control within five feet from the roadside was also poor, less than 35 percent control achieved; Plateau and Journey combined treatments in the burned areas, resulted in greater than 90 percent control of cheatgrass achieved throughout the area except within five feet from the roadside where less than 35 percent control was achieved; germination of drill-seeded desirable plants was excellent from the roadside to halfway to the fence and all seedlings appeared healthy, Plateau, Journey, and Telar combined treatments resulted in greater than 90 percent control of cheatgrass achieved throughout the area and germination of drill-seeded species was good; however, leaf yellowing was occurring in about half of the plants.
Applications conducted during 2007 include herbicide applications using Telar and Roundup combination, other herbicide treatments to reduce kochia and mustard species, mowing applications, as well as mechanical seeding applications with native and non-native fire resistant species to control annual grass competition.
Future objectives include collecting data and establishing monitoring sites to monitor residual cheatgrass control and seedling establishment (to be completed in fall 2007), identifying additional sites and acres for Plateau and Journey applications, and treating remaining acres using herbicide, mowing and mechanical seeding applications.