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Digging dooms old Siberian elm

Thu., Aug. 20, 2009

Irrigation project gets too close to tree’s roots

When a new irrigation system was installed in Comstock Park this summer, some of the digging got too close to old trees, damaging their root systems. An old Siberian elm at the Northwest corner of the park, facing 29th Avenue, was the first one to be cut down, and more may follow.

“The urban forestry staff is spread pretty thin these days, and we weren’t monitoring the project closely enough,” said Steve Nittolo, the city’s horticulture supervisor. “Also, the irrigation contract wasn’t as specific in some areas as I would have liked for it to be. Obviously, this is something we don’t intend to have happen again.”

The Siberian elm had other problems, too.

“It wasn’t in the best location as it was right next to a rock wall, and then it lost some roots on the other side of the rock wall,” Nittolo said. The tree’s location next to the sidewalk and under power lines could have led to other hazards, also considered before its removal.

Nancy Goodspeed, spokeswoman for the Spokane Parks and Recreation Department, said in a statement last week that the department has re-examined specifications and the monitoring process to prevent similar damage to park trees.

“The Parks and Recreation Department has also committed to the Comstock neighborhood to plant three new trees in the park for every damaged tree that may need to be taken down,” Goodspeed said.

For private property owners, the project offers a few lessons.

Steve Nittolo, horticulture supervisor for Spokane, said anyone considering work around large, old trees should consult with a certified arborist.

“An arborist can help you evaluate where the root system is,” said Nittolo, adding that many old trees’ roots stretch to the drip line at the edge of the canopy.

“Hand digging is not the preferred method of digging around trees,” said Nittolo, “because once you see the root it’s most often because you severed it.”

Arborists have special digging tools that use air or water to gently tunnel under or around roots without damaging them.

Street trees in strips between sidewalks and streets are public trees, but their care falls to property owners.

“Our goal with the regulations is to avoid a net loss of trees,” Nittolo said. “We want to preserve the urban canopy the best way we can.”

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