Planting trees to save riverbanks

One cottonwood sapling at a time, a local conservation program is slowly stemming the tide of erosion along the Flathead River’s ever-changing course through the lower Flathead Valley.

Landowners along the river’s lower 22 miles face a unique challenge from Séliš Ksanka Ql’ispé Dam (formerly Kerr Dam) near Polson as the annual raising and lowering of water levels extends the surface of Flathead Lake upriver each spring.

“What we’d usually see is a peak of flooding in the spring, then a slow decline in the fall and winter,” said James Dillon, the newly arrived Flathead River steward under the Flathead River-to-Lake Initiative.

Driving his pickup truck along a bumpy dirt road between the river and still-bare fields of Diamond B Ranch, he compared the root systems of riparian trees to rebar that would otherwise stabilize the banks.

“Those roots naturally chase the water level down as it recedes,” he said. But without the natural ebb and flow governing that underground growth, the trees’ root systems remain shallow, allowing the artificial flows to undercut the banks until the overlying trees slough off.

Dillon arrived in the valley this year as the new Flathead River steward, a position, funded by Big Sky Watershed Corps, the Flathead Lakers and Montana Fish, Wildlife and Parks. He helps coordinate efforts by state, federal and tribal agencies, area nonprofit organizations and the local river commission and conservation district to restore riparian habitat and secure easements in the lower valley.

“We do a lot of general education and outreach, teaching best management practices and the importance of riparian forest,” he said. “The other arm of what we do is active restoration.”

Recently seven members of the Montana Conservation Corps worked a 300-by-50-foot plot of future riparian habitat on the riverside buffer required under the ranch’s conservation easement. Crouching over a matrix of holes in a black, plastic weed mat, they carefully placed the tiny saplings in the rich soil underneath — roughly 2,300 over the course of the week.

Maeve Wrixon, who returned to the corps this year to be a crew leader, said her first season with the service-learning program inspired her to learn more and pass the experience on to the next crop of crew members.

“It was kind of a new adventure,” Wrixon said. “It made me want to come back, learn more about the land and what’s happening on it.”

The restoration work requires attention to detail, she added, along with an understanding of proper planting techniques on the ecologically sensitive riverbanks.

“One wrong move in planting them and the roots could grow the wrong way, or they could grow too close together.”

Stretching along a mile of Jerry and Aileen Brosten’s riverfront ranch, tall deer fences marked several identical plots now populated with the beginnings of an aspen and cottonwood forest. At 5-foot intervals between the young trees, chokecherries, sandbar willows, Woods’ rose, Drummond’s willows and redosier dogwoods had been planted to create an understory of native riparian shrubbery.

Franz Ingelfinger, a restoration ecologist with Fish, Wildlife and Parks, said he and Dillon are working to “scale up” their efforts, testing out more efficient techniques such as cottonwood pole planting, in which a higher volume of cuttings taken from more mature trees can be planted than traditional transplanting.

Dillon added that cottonwood plantings are especially important in the lower valley, where flood mitigation by the dam comes at a price to the natural ecosystem.

“The dam is great for [protecting] homes, but certain species, cottonwood in particular, spread their seeds during flood events,” he said.

It’s slow work, but over time, the efforts of conservation-minded individuals and partnerships such as the River-to-Lake Initiative have permanently protected more than 41 percent of the lower Flathead River flood plain.

The river steward program was created in 2013 and has since fenced or planted over 20,000 feet of habitat lining rivers and streams on 12 properties. Prior to the program, many of those same partners planted about 11,000 native trees and shrubs in the area since 2008.

For the future crew leaders such as Connor Adams, the learning experience adds value beyond the greening of river and stream corridors.

“At Foy’s Bend, you can see the erosion all the way up to the houses, built only 50, 60 years ago. It’s interesting to see how much everything is connected,” Adams said. “This ecosystem is never going to be what it’s supposed to be. ... But you have to find a happy medium between conservation and allowing people to live their lives, too.”

Reporter Sam Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.