"Tough decision" to remove towering cottonwood

Cottonwood Square in Niwot is about to have one less cottonwood tree. Boulder County Public Works is planning to cut down a tree on the south side of Niwot Road, just east of 79th Street. It's estimated to be 50 to 100 years old. The tree is decaying and risks falling over, according to Boulder County arborist Cathy Thiltgen.

"It was a tough decision, but ultimately we had to make it safe for the community. We just don't want anything terrible to happen," Thiltgen said. She and arborist Mary Tiernan evaluated the tree and discussed it at length, even sleeping on it before reaching their conclusion. "We are normally very conservative. We don't like to [take down a tree if we don't have to. We take into consideration the history of the town and what it means to folks."

There is no way of knowing the exact age of the tree until it's cut down. Cottonwoods are native to the area, but Thiltgen said settlers also planted them. There used to be a farmhouse on the corner of 79th Street and Niwot Road. It burned down in 1986. The tree sits on the edge of an old irrigation ditch. Having access to water may have been a factor in creating an arched cavity at the base.

Thiltgen used a five-foot probe and reached it into the cavity and up inside the trunk. Nothing stops it. She waved the probe around in the tree's interior, which indicated a wide space.

The assessment also focused on two sizable, above-ground roots to either side of the trunk called "reactionary wood," something a tree grows when it is compensating to support itself. Tiernan taps the base of the reactionary wood with a mallet. Thud. A big difference from the sound of the solid wood on the top of the root.

The arborists determine that the reactionary wood is also decaying and not strong enough to make up for the hollowing trunk. Thiltgen doesn't think a fall is imminent, but the risk is there. A strong wind could cause the tree to topple or branches to come down with potentially catastrophic consequences for pedestrians, motorists or the building that formerly housed Lucky Pie restaurant.

Removing the tree coincides with an effort to beautify Cottonwood Square and improve pedestrian connectivity with 2nd Avenue. Capital Program Coordinator Tim Swope with Boulder County Public Works said there is a plan to widen and extend the sidewalk from 79th Street to the Niwot Market. The project would include filling in the former irrigation ditch. "Because we were doing the project, we took a look at that tree to figure out if it would survive. Turns out it won't survive the project, and it won't survive much longer as well," he said.

The ditch no longer carries a steady flow of water, but it does capture overflow from rainstorms. That overflow would likely be managed by adding curbs and gutters along Niwot Road, according to Swope. He said the design should be finished this summer with construction beginning as soon as the summer of 2022.

The project would cost between $100,000 to $200,000, paid for through a partnership between the three owners of properties in Cottonwood Square, the Niwot Business Association, the Local Improvement District (LID) and Boulder County. It was initially conceived as part of the 2012 Niwot Transportation and Connectivity Plan.

Chuck Klueber, Streetscapes volunteer for the Niwot Business Association, said that widening the sidewalk and filling the ditch could allow the sculpture garden at 79th Street and Niwot Road to be extended east as a way of enticing people to move toward the businesses in Cottonwood Square.

Boulder County Public Works is willing to leave the cottonwood stump if the community wants to do another tree carving like the ones further west on Niwot Road, which were carved on willow tree stumps. But there appears to be no appetite for that since the tree carvings to the west are rotting due to the continuing uptake of groundwater. The artist, Eddie Running Wolf, died last year, so a new artist would have to be commissioned for additional carvings.

"We've come to the conclusion that cottonwood trees are not good candidates for tree carving because they rot too quickly, deteriorate too quickly," said Klueber. There is an ongoing effort to preserve Running Wolf's carvings. A 3D image has been made and Klueber said there are discussions about replicating the carvings in metal.

Boulder County is asking the public for comments about the plan to cut down the tree and ideas on what to do with the wood. In some cases, wood from historic trees has been doled out to artisan woodworkers to commemorate a tree and the history of the area. Leave comments here through May 31.