Beavers chewing up trees at water’s edge along Riverfront Park

Gnawing nocturnal visitors to Spokane’s Riverfront Park had officials scrambling to save towering cottonwoods from a watery grave this winter.

A flourishing beaver population along the banks of the Spokane River, stretching east from the 100-acre park in the city’s downtown to the shores behind Gonzaga University at least, is being blamed for gashes in the trunks of shoreline trees. The targets are not only those in the willow and poplar families that are staples of the beaver’s diet, but also pine and hawthorn trees that don’t have the same type of bark the creatures prefer.

The activity is puzzling experts and drawing the attention of a sleuthing class of preschoolers.

Joe Cannon, a restoration ecologist with the Lands Council in Spokane, said it’s the most active he’s ever seen the semiaquatic rodent that has often crossed paths with urban dwellers in the city by the falls.

“They’re always here, they’re just having a bigger presence this year than they’ve had,” said Cannon, standing amid a row of trees near Lake Arthur on Gonzaga’s campus last week that showed the telltale signs of beaver chewing.

Cannon studied at Oregon State University in Corvallis, eventually becoming a member of the Land Council’s beaver project. His work includes consulting with property owners about damage to trees, including the owners of the Spokane Convention Center and condominiums on the river’s southern edge. There, too, beaver colonies are believed to be responsible for tree damage that has stripped the bark from several shoreline trunks and shrubs.

Jeff Perry, arborist for the City of Spokane, said there’s always been beaver activity in Riverfront Park, but now it’s stretched to areas previously untouched. A row of about a half dozen cottonwoods near the Forestry Shelter, across the river from the Red Lion Hotel and near Avista’s upper dam, have been wrapped with wire in an attempt to prevent further damage. That was after willows near the Lilac Bowl had been targeted earlier in the winter, leading to the felling of at least one tree into the water, said Perry.

“The big thing, is there’s been a lot more activity in the park. We usually see it in the north channel, but now we’re seeing it in the south channel,” Perry said.

It’s that activity that caught the attention of Chelsea Inman’s preschool students at the Community Building Children’s Center. Groups of a half-dozen students, between the ages of 3 and 5, take routine tours through the park and began spotting beaver activity in late November, Inman said.

“We’ve been bringing students to the park for years and never seen beaver activity before,” Inman said.

Students found some downed saplings near the upper dam, and followed the wood scraps “Scooby Doo-like,” Inman said, to the damaged trees to the west. The trail included some trail-marking posts on the bridge leading between Havermale Island and the north bank of the river, suggesting the beavers became confused and started gnawing the wooden markers, believing them to be tree trunks, she said.

On Monday afternoon, Inman’s students gathered in a circle, as they do twice a day, to talk about their investigation and what they learned about the eager animal.

“I think it’s a good idea, to let everyone know that beavers were chewing our trees,” said Olivia, 4, who also said her favorite animal was a beaver.

Nelson, 5, said it was important for beavers to have a source of food in the park, so they didn’t venture into other, more dangerous parts of town.

“They can only eat the park trees, and not the other trees in our city,” Nelson said. “We couldn’t have any fruit, or apple trees, or any pears, or any cherries to eat.”

Nelson’s not far off. The pages of The Spokesman-Review throughout the years show that beavers have made their way into urban areas of Spokane. In October 1937, the city’s utilities director discovered the patriarch of a beaver family sleeping beneath a steam pipe beneath Howard Street downtown. And in January 1956, the newspaper published an obituary for a beaver shot and killed by a police captain on the Post Street bridge, believed to be one of a colony “that has been chewing down trees on the Gonzaga campus.”

“Who knows, perhaps the little monster decided to go on to greater things than than the trees. Maybe he was eying the bridge,” the newspaper quotes one “passing patrolman” as saying after the shooting.

The children in Inman’s class haven’t yet been able to spot a beaver. The creatures are nocturnal, doing most of their feeding and work at night. Inman said she’d love to have her students don some headlamps and continue their detective work at night, but the planning might be too difficult.

“We’re mostly studying what we see,” Inman said.

That’s also what Cannon’s been doing, consulting with both the city and the convention center owners about what to do. Cannon’s expertise also includes live-trapping the animals, a strategy he considered in the park areas but decided against.

“It’s kind of a liability issue if I’m setting live traps, it’s kind of big clamshell thing that closes on them,” Cannon said. “If somebody steps in it, it’s bad news.”

The beavers almost certainly aren’t considering a dam with the wood they’ve targeted along the river banks, Cannon said. The creatures will dam still waters, but along the banks of the Spokane, they usually build lodges and dens with concealed entrances beneath the water’s surface.

Cannon pointed to some stark white branches stuck in a shallow cove of the Spokane River near Gonzaga last week as a likely source of food. It’s also a sign the animals were nearby, in addition to the freshly chewed tree trunks scattered about.

“That’s a good indication there’s a den there,” he said, pointing beneath the surface of the slowly moving river. “They can comfortably feed there.”

Inman’s class has their own theories about the increased beaver activity. Less foot traffic in the park, due to the construction that has shuttered the U.S. Pavilion and closed large swathes of meadow and prairie areas typically open to visitors, might be an explanation, the students surmised.

“But it could also be a sign of the health of the river, and that’s a good thing,” she said.

If the city were to replant the cottonwoods that have been damaged, the work may have to be approved by a committee overseeing any landscaping work so close to the shoreline of the rapidly moving river below, Perry said. There is a permit exemption for environmental restoration work.

Cannon thinks those turbulent waters are as good an explanation as any as to why the signs of the beaver are so prevalent this spring, along with an expanding population that can live comfortably and free of natural predators along the banks of the Spokane.

“I think they kind of get trapped a little bit, between the dam and that serious whitewater,” Cannon said. “It’s kind of the conclusion I make. Every year, they get there and eat those trees. But during the summer, they’ve moved on to greener pastures.”