The literature review for this project identified a lack of research on the relationship between road maintenance and noxious weed dispersal. Research should be conducted to identify how specific maintenance tasks influence the establishment and spread of weeds on roadways. This information could be used to determine which types of maintenance should be modified and how much benefit could be achieved. The research should include species, distance, and quantity of weed seeds and other propagules that are spread or transported during each maintenance task.

Examining potential weed transport mechanisms during road maintenance would establish more precisely when and how weeds are likely to be spread and how that spread may be reduced or eliminated.

Consider developing grader-mounted technology for "last pass" seeding of desirable grasses along road shoulders. A gradermounted seeding mechanism would reduce seeding costs and make reseeding more practical, given limited maintenance budgets.

Common gorse is an imported shrub with lovely yellow flowers and
impressive thorns that displaces native shrubs and disrupts natural
habitat. It is particularly aggressive in coastal scrubland environments.
—Photo by Norman E. Rees, USDA Animal Research Service.
Image 0021012 courtesy of Forestry Images.

Dodder is a parasitic vine that is fed from host
plants. It looks like a bright yellow thread
among plant stems and leaves.
—Photo by the USDA Animal and Plant Health Inspection
Service, Oxford, NC, archives.
Image 1149113 courtesy of Forestry Images.

Road maintenance is essential for safe access to public lands. Noxious weed species frequently colonize roads and are likely to be spread during road maintenance. Road maintenance can be designed to minimize weed spread and reduce weed seed production. The work should not be undertaken without coordination between the maintenance crew and the noxious weed specialist.

Western brackenfern has invaded this old tree harvest unit on the
Walla Walla Ranger District in Washington.
—Photo by Dave Powell, USDA Forest Service.
Image 0976092 courtesy of Forestry Images.