Attenuation and Effectiveness of Triclopyr and 2,4-D Along Alaska Highway Right-of-Ways in a Continental and a Coastal Subarctic Environment.

摘要

Highway right-of-ways (ROW) are an essential component of the public highway transportation system. Once a highway ROW is established regular maintenance is necessary, chiefly vegetation management, to ensure functionality and integrity of the corridor. Vegetation management on highway ROW is desirable and necessary for a variety of reasons including the promotion of safe and clear line-of-sight distances, visibility of signs and other fixtures, reduction of fire hazard, snow or dust drift control, prevention of icing due to shading and to provide adequate drainage in roadway ditches. As an example of the necessity for ROW maintenance, during the winter of 2003, Alaska drivers hit 1,322 moose. At an average cost of $15,000 in automobile damage per collision, moose/car accidents cost Alaskans over $18 million a year (Stigall, 2005). Sufficient vegetation control removes the food source from the roadside as well as improves driver visibility, thus increasing reaction time when moose are present in a highway ROW, reducing the probability of collision. Vegetation control also aids in maintaining structural integrity of the roadbed and road surface, which can be deteriorated by pervasive root development (Gangstad 1982). The primary objectives of vegetation management are prevention, control and eradication of weeds. In the context of vegetation management weeds are defined as plants that are competitive, persistent, destructive and interfering with human activities. Vegetation control on highway ROW can be achieved in various ways including mechanical, chemical, biological and preventative weed control, used individually or in combination. In practice, most of the emphasis and effort spent on controlling weeds is centered on mechanical and chemical methods (Ross et al., 1985).