August 7, 2000
Attack of the killer roots
by Bronwyn Wilson
No one should be fooled by their peaceful appearance. This row of stately London Plane trees looks innocent enough, lined up along NE Woodinville-Duvall Rd at the 140th Ave. NE intersection. The trees, adjacent to Bank of America, were planted in the 70s when Gerald Ford was president and have flourished over time. Today they stand forty or fifty feet tall spreading out their massive branches to shade the sidewalk and street below. But looks, in this case, are deceiving. The fact is, these innocent-looking trees are bent on destruction. Lurking beneath the surface, the trees' root system wreaks havoc with whatever stands in the way. The roots are interfering with the underground infrastructure that controls the sensors to the traffic lights. They're causing the sidewalk to buckle and they're pushing up the asphalt in the road. This concerns the City of Woodinville. "It's not easy for pedestrians to pass on the sidewalks, especially those in wheelchairs," said Becky Perkins, Woodinville's city planner. "At the same time, losing the trees will impact the community," she added.
The ravaging roots have been on a destroy mission for some time now. "The City has been looking at this sidewalk/intersection restoration project since '96," Perkins said. "We've had three arborists look at the whole area and we've assessed each tree." The question before the City is what to do now. The trees are valuable enough for the City to make efforts to save the them ‹ at least some of them. One effort includes hiring certified arborist, Ian MacCallum. On August 9th, MacCallum will cut out a small area of the street to look at the roots and determine if pruning is a viable solution. If his test proves that it is, the next step is to dig up large sections of sidewalk and road to get at the extensive root system. After pruning, underground plastic barriers would be placed around the roots to keep them from causing future punishment to Woodinville's roads and sidewalks.
"London Plane is a really great tree for harsh conditions and they can thrive anywhere," MacCallum said, explaining why King County planted this particular type of tree next to a busy street. He added that the American Elm was once the tree of choice for municipalities to plant along city streets. Like the London Plane, the elm is hardy and will tolerate poor conditions. However, Dutch Elm disease wiped out many elms in the early 70s. It was at that time cities looked for a replacement tree and picked the London Plane as their next choice. The City of Seattle began planting London Plane trees and soon other cities in King County followed suit. Back then, the trees' destructive ways weren't considered. "They start to rear their ugly head later on," MacCallum said. And not only have they reared their ugly heads, but their ugly roots. "They break up sidewalks, they break up curbs, they crack asphalt," MacCallum said.
Although it would appear to be less expensive up front to remove the trees, Woodinville doesn't take its trees lightly. Woodinville, named "Tree City, USA" through the National Arbor Day Foundation, appointed a Tree Board to focus on tree matters. One of those matters concerns a Street Tree Plan, a 3-10 year plan phasing trees out over time and replacing them with trees that won't grow into the power lines or have roots that interfere with traffic lights or add mini-hills to level sidewalks. Another matter for the Tree Board is to honor trees that bring beauty and stature and grace to Woodinville with the Heritage Tree Award. Two trees honored include: the Little Leaf Linden, which stands in all its glory at Molbakís and is over a hundred years old; and the majestic Spanish Chestnut at NAPA Auto Parts, also over a hundred years old.
Though the London Plane trees aren't even close to a hundred years old, the trees have added charm to the city with their leafy green canopy. Their fate, however, is now in the hands of the City and will be determined within the next couple of weeks. According to Perkins, some of the trees will have to go no matter what the test results show. And the City has its sights on the replacements. "We're looking at a couple of different species," Perkins said. One possible replacement is the Lavalle Hawthorn. This beautiful tree intensifies from bright glossy green in Summer to a bronze-green in fall. Another tree being considered is the Bowhall Maple which makes a splashy show of color in fall.
MacCallum concluded, "The ideal is to put in trees that won't have aggressive root systems, won't grow up into the power lines and won't have to be whacked." Whatever the outcome, the City will continue to seek ways to beautify Woodinville's landscape with trees.
For anyone wanting to nominate a great-looking tree deserving of a Heritage Tree Award, contact Becky Perkins at 425-489-2700.