Digging dooms old Siberian elm

Irrigation project gets too close to tree’s roots

Thu., Aug. 20, 2009

By Pia Hallenberg piah@spokesman.com (509) 459-5427

Looking out for the big guys

Steve Nittolo, horticulture supervisor for Spokane, said anyone considering work around large, old trees should consult with a certified arborist. Arborists have special digging tools that use air or water to gently tunnel under or around roots without damaging them, he said.

Right-of-way trees are homeowner’s responsibility

Is your tree a right-of-way tree?

The property owner is responsible for the maintenance and care of any trees growing in the strip between the sidewalk and the street.

The public right of way varies from 6 feet to 15 feet from the street, depending on the property’s location. A few rules, according to Steve Nittolo, horticulture supervisor for the city:

If a right-of-way tree dies, the property owner is responsible for having it taken down, removed and replaced.

Right-of-way trees can only be pruned by certified arborists. Property owners may remove small branches that obstruct sidewalks or driveways, but only certified arborists can obtain the necessary pruning permits to really cut back the trees.

A permit is needed to plant, prune or remove a right-of-way tree.

Property owners may plant trees directly under power lines, but must pick trees that will not reach past the power lines when mature.

“You want to find the right tree for the right place,” Nittolo said. If a big maple dies, it shouldn’t automatically be replaced with another maple.

“We require that you plant as large a tree as possible, depending on the rooting space and any overhead power lines,” said Nittolo. “And remember, no topping of existing trees. Cutting the top off your tree is never a good idea. It leaves the tree more susceptible to disease, and it can become a structural hazard.”

For questions about the care of street, right-of-way and other trees, call (509) 363-5495.

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.”