Isolated
by Emily Johnson
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Jim Mcdonald of the WSDOT points out trees that will need to be cut back to avoid interfering with sight on I-5. |
South of Bellingham, in a median near Lake Samish, McDonald, regional maintenance superintendent for the Washington State Department of Transportation, turns on his flashing yellow light and pulls his WSDOT vehicle into an area known as the Barnes Creek turnaround. Wearing his bright orange safety vest, he steps out into a small clearing of mowed grass.
The plants and animals in the median live in a human controlled environment between the concrete and unending traffic. I-5’s construction isolated the median from surrounding habitat. WSDOT manages everything in the medians to keep roads safe and minimize impact on nearby environments.
McDonald said plants help stabilize slopes and filter and retain stormwater. WSDOT prefers to have certain native plants in medians. Those plants help WSDOT meet their goal of having self-sustaining, low-maintenance vegetation. Native plants are easier to manage than nonnative plants because they don’t spread out of control.
WSDOT prefers native plants, said Sandy Stephens, WSDOT operations and maintenance water quality policy manager, but not all native plants are suitable because of safety concerns.
"Alders are a very dangerous tree because when they get to a certain size they have a tendency of freezing and cracking," Stephens said, "and they will fall onto the highway system and can present a safety hazard to the traveling public."
Stephens said more desirable plants are smaller and low-growing.
"Salal is an excellent [example]," said Vikki Jackson, former president of the local chapter of the Washington Native Plant Society. "They don’t get to a very large size but they provide a lot of shading."
McDonald said WSDOT tries to minimize impacts on neighboring habitats and the animals that live there. At the same time, they try to discourage animals from using the medians.
"We don’t encourage deer to use the right of way but there’s not much of a good way to prevent that," McDonald said.
Anytime wildlife lives near the freeway, the animals will find their way into the right of ways sometimes, he said.
Keeping the visual corridor clear by mowing roadside vegetation is important so people and animals can see each other, McDonald said.
Red-tailed hawks are one species that has adjusted to I-5, Jackson said.
"Red-tailed hawks have found a particular niche and have flourished along the I-5 corridor feeding on the voles that live in the grasses on the side of the road," she said.
Stephens said WSDOT also controls aquatic habitats. Green reflective posts mark areas along the freeway that hired wetland biologists identified as important for fish habitats. These "fish stakes," as McDonald calls them, are posted along the freeway as part of WSDOT’s sensitive area identification program.
"(The posts) provide guidance to our maintenance crews so that they know when to apply (practices) that will eliminate and reduce impacts on streams and wetlands and water bodies," Stephens said.
Another important part of vegetation management, McDonald said, is preventing infestations of noxious weeds.
Any plant dangerous to people, animals or native plants is considered a noxious weed, said Ray Fann, 26-year member of the Washington State Noxious Weed Control Board and 1980 founder of the Whatcom County NWCB.
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The plant with a yellow, daisy-like flower contains toxins that can shut down a horse’s or cow’s liver the same way alcohol affects a human’s liver, Fann said.
"I would say 90 percent of weed problems begin on highway right of ways," Fann said.
A common way for weeds to be spread is the transportation of agricultural materials like hay, said Laurel Shiner, Whatcom County Noxious Weed Board coordinator since 1989. Materials, including seeds, might blow off of trucks.
Another common way for weeds to spread is by getting picked up on vehicle undercarriages or on radiator grills, as well as seeds getting blown up and down the I-5 corridor from car movement.
"Weeds don’t move from place to place by themselves," Shiner said, "people move weeds, whether they know they’re doing it or not."
Knapweed, a green-grey, thistle-like plant with pink or lavender flowers, is a common weed along I-5, Shiner said.
"Knapweed is probably one of our most notorious hitchhikers," she said. "They’re a high priority along the I-5 corridor. Some of the knapweeds grow at the approximate height of most radiator grills. I think it’s some sort of weird evolution thing."
According to Washington state law, it’s the responsibility of the landowner to control noxious weeds. The law also gives local weed boards the authority to enforce weed control.
"Anybody that owns property in this county and has a noxious weed on it is destined to hear from us, whether they want to or not," Shiner said.
Shiner said the local weed board works closely with the WSDOT.
"About once a year someone from the local (weed) board comes to
help us with weed identification," McDonald said.
"They tell us about new laws, new regulations."
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Laurel Shiner points out knotweed in Hoover Park. Knotwood is considered a noxious weed. |
Shiner said herbicides are usually the last option considered for controlling weed populations.
"Herbicides can be a very useful tool when they’re used well," Shiner said. "If you’re going to do vegetation management you have to look at the target plant. You have to learn all its idiosyncrasies before you can really approach it well.
Herbicides can certainly be a useful part of that. They are not the only tool, though."
Shiner said many times in travel corridors, herbicides could be the best option.
"(In travel corridors) it’s economically wise to use herbicides on the right target plants at the right time of the year, so you’re not using too much and that you’re doing what you’re out there to do, and not wasting time," she said.
McDonald said the maintenance crew is trained and certified to apply herbicides using the proper methods.
For McDonald and his maintenance crew, managing vegetation is a big issue, but he said it’s interesting work. Working in the medians provides him with a close-up view on an area looked at every day but rarely noticed.
After finishing his tour of the Barnes Creek turnaround, McDonald pulls carefully back in to the rush of semi trucks and commuters. Without missing a beat, his eyes are again surveying the roadside for anything amiss in the medians.