Highway Corridor Responsibility
From: Exotic Pests of Eastern Forests, Conference Proceedings - April 8-10, 1997, Nashville, TN, Edited by: Kerry O. Britton, USDA Forest Service & TN Exotic Pest Plant Council
As highways cross the nation they provide safe travel for the vacationers,
commuters, truckers, the military, farmers, congressmen, our families, and
friends. Highway corridors provide safe passage for many plant invaders
as well. Highway vegetation managers manage millions of acres of rights-of-way
that cross your land. It is imperative that we understand each other's management
strategies and cooperate as much as possible. If we do not, plant invaders
that have no respect of political boundaries will prevail. This paper examines
why roadside vegetation managers operate the way they do. Both negative
and positive examples of current practices are noted. Future practices are
State and interstate highways are typically maintained by state highway
agency crews. A few states, such as Wisconsin and Tennessee, engage county
maintenance forces to do vegetation management. It should be understood
that the Federal Highway Administration does not own or have management
responsibilities over the many acres of roadsides that parallel our nation's
roadways; but rather serves as an advisor and information resource for all
the states. States do not own all of the roadsides, but rather lease much
of the right-of-way. As a consequence, adjacent landowners often participate
in vegetation management on these lands. Some states allow farmers, in particular,
to harvest hay from the rights-of-way during drought years. Utility companies
have access to these same roadsides. The intended users of a roadside are
errant vehicles that require a recovery zone to minimize injury. Of course,
that same land accommodates directional and information signs. The roadsides
are, therefore, operational areas for many uses. These uses must be considered
by vegetation managers.
Each state makes vegetation management decisions based on the years of
experience in that state. Vegetation management policies have evolved differently
in different places due to climate constraints, policy changes, public demand,
and all the uses mentioned. Safety will always be the number one requirement
affecting decisions. In the past, many decisions were affected by an unwritten,
but widely known, policy of managing our nation's roadsides as if they were
our nation's front lawns. This notion prevailed in the 1930's, when many
state roadside development programs were begun. When herbicides became technically
available in the 1950's, spray-mow approaches became the norm to give the
public that manicured look. In the 1970's, after the energy crunch, roadside
maintenance quickly changed due to the increased cost of labor-intensive
management. Alternatives were sought, and in many states, more ecological
solutions were found. The idea of "working with nature," reducing
chemical use, timing mowings, and adding prescribed burns, defined the ecological
approach. As new management tools were sought, the idea of integrated roadside
vegetation management (IRVM) emerged as the common sense approach of the
80's. What if we no longer used a blanket approach, or one size fits all,
but used the right tool for the right problem, site-specifically! With that
background in common, each state's vegetation policy continues to be unique
because of the other factors that influence decisions.
Some decisions made by state highway agencies (SHA) that have had negative
environmental consequences, have included nameless states who have: l) mowed
around and saved Tree of Heaven (Ailanthus altissima) to save a tree, 2)
planted Black Locust (Robinea pseudoacaia) because the seedlings were free,
3) planted Purple Loosestrife (Lythrum salicaria) for beautification purposes,
and 4) pictured Kudzu (Pueraria lobata) in a wildflower brochure, and so
on. The public, who knew about the predictable consequences of these invasive
plants, viewed these decision-makers as thoughtless.
Some SHA decisions with positive environmental consequences include:
l) the Florida Department of Transportation, motivated by the invasion of
Tropical Soda Apple, now requires weed-free certification of sod used in
construction projects, 2) the Tennessee Department of Transportation successfully
funded a biocontrol study on Musk Thistle, 3) the Utah Department of Transportation
has trained its workers to identify and control new invasive plants at Utah's
borders, 4) a six-State partnership of Texas, Oklahoma, Missouri, Kansas,
Iowa, and Minnesota have taken inventory and are developing a coordinated
vegetation management plan for a highway corridor from Mexico to Canada,
5) the Iowa Department of Transportation has backed an ecotype approach
to native seed production and use on planting projects to outcompete noxious
weeds, 6) a coalition of SHAs and industry recently produced a guide to
Integrated Roadside Vegetation Management, and finally, 7) in 1997, four
State Departments of Transportation endorsed support for the National Strategy
for Invasive Plant Management. These states demonstrate a proactive trend
towards highway corridor responsibility.
It will take time for all states to get on board with the IRVM approach.
They continue to make the best decisions they can with the information they
have at the time. This author can foresee a time when each state has its
own IRVM plan for all segments of highways it has inventoried. In the meantime,
exotic plant pests continue to move across the country through highway corridors.
Teasel has been seen from Arkansas to Idaho. Russian olive spreads from
the midwest to the southwest. Johnsongrass migrates from the south northward.
Kudzu now adapts to cold climates! Purple loosestrife is spotted in every
state. Leafy spurge and knapweed extend from the deciduous forest throughout
Obstacles to highway agencies controlling these invasive species remain.
Many states in the northeast and the south still do not have state noxious
weed lists that help identify priorities for IRVM. Some state agencies have
not yet embraced IRVM. Additionally, some SHAs are still planting invasive
plants like Oxeye daisy, dame's rocket, queen anne's lace, smooth brome,
sweet clover, and crownvetch. All of these are known to be invasive by land
managers. All appear on one or more state's noxious weed lists and, therefore,
should be suspect in adjacent states. To further complicate invasive species
control, funding for this roadside activity has not been historically significant.
As state agencies "do more with less," invasive species control
or integrated roadside vegetation management will have less resources. These
are the obstacles that roadside vegetation mangers are up against. They
need public support and influence to obtain the resources they need to learn
more and do better!
Randall, John, and Jan Marinelli (eds.). 1996. Invasive Plants, Weeds
of the Global Garden.Brooklyn Botanic Gardens, Brooklyn, NY.
Et al. 1997. Pulling Together, National Strategy for Invasive Plant Management.
United States Fish and Wildlife Service, Washington D.C.
Harper-Lore, Bonnie (ed). 1995. Greener Roadsides. Roadside Pest Plants.
Federal Highway Administration, Washington D.C.
Walvatne, Paul (ed.). 1996. How to Develop and Implement an Integrated
Roadside Vegetation Mangement Program. The National Roadside Vegetation
Management Association, Newark, Delaware.