Christmas trees help prevent shore erosion

By LAURA BEHENNA

Bigfork Eagle

Old Christmas trees can help save the shore of Flathead Lake from excessive erosion, according to Dr. Mark Lorang, a University of Montana assistant research professor at Flathead Lake Biological Station in Yellow Bay.

Lorang has been working with Friends of Bigfork Schools (FOBS) to collect discarded Christmas trees he can use to make “brush bundles” that will protect the north shore from eroding away the wetlands at the mouth of the Flathead River. His plan is modeled on one that has proved successful in central California, he said.

“I have been working on levee erosion issues in the Sacramento River Delta for over eight years now, and this bush bundle technology has been used there with great success,” he said.

Bundles of baled trees are laid between two parallel rows of vertical posts imbedded close to the endangered shoreline. The wall of bundled trees allows river sediment to build up behind it while slowing wave and current action that could eat away the shore.

“Once you get sediment deposition, then you can replant with willows and alders, getting their roots established at the water level where boat wakes, wind waves and river currents cause erosion,” Lorang explained. “The added root strength is enough to control erosion and the growth of those plants provides a valuable riparian shoreline buffer.

“The other added benefit is that we do not have to mine gravel and boulders from another site to use as rip-rap. Pretty much a

win-win solution.”

The wall of brush bundles requires some maintenance, “but we have an annual supply of a renewable resource: Christmas trees and other small trees for poles,” Lorang said.

The scientist hoped to gather at least 1,000 trees for the project, but donations have far exceeded that goal. He estimates getting about 3,000 trees from individuals, tree lots and the City of Kalispell, and he plans to use all of them. He’s working with other agencies, including Fish, Wildlife & Parks and the Department of Natural Resources Conservation, to expand the project in future years.

“There are miles of eroding shoreline on the lower Flathead River between the lake and Kalispell where this approach could be used successfully,” he said.

“We have had great response from the community,” he said. He’d like to keep the community involved by leading field trips for school classes and adults interested in learning about the north shore and the erosion control projects.

“The more people we get involved, the better the community becomes connected to the local landscape, and that is a good thing,” he said. “Just taking the time to donate a Christmas tree is what first connects people.”

Lorang will oversee the Installation work, which will start in March or April and take about a month to complete, he said. He hopes the bundles will be placed in time to start settling the abundant sediments the river carries down to the lake during the annual spring run-off.

The Montana Conservation Corps has offered to help, and local contractors will bail and haul the bundles and poles and do the installation work “because they have the required equipment and can ensure that the project gets completed,” Lorang said. Bigfork tree farmer Mark Schiltz has donated a day of his time and baling equipment to bundle many of the trees.

Lorang expects the project to result in plenty of new plants whose roots will stabilize the shoreline and allow the north shore to nurture diverse kinds of native wildlife.

“I expect to see growth of riparian trees and shrubs like cotton woods, alders and willow, [and] other plants like bullrush, cattails and sedges,” he said.

Lorang will use both simple and advanced technologies to measure how well the Christmas tree brush bundle project is working in future years. For example, pins and rods placed in the sediment will help him and his students measure how much the shore is building up (or eroding) over time. They also will measure and record the types and sizes of plants growing along the shore. More advanced equipment will measure water depth around the brush bundles and across the river, how fast the current is moving, and the size of boat wakes. Wind and boat wakes both create waves that erode banks, especially hear the river mouth, Lorang said.

The researcher plans to publish the results from the project in an international peer-reviewed science journal, probably “River Research and Application,” he said.

People who would like to learn more about this shoreline restoration project may call Dr. Lorang at 982-3301, ext. 231.

Friends of Bigfork Schools will receive a donation of $3,000 from PPL Montana for its role in organizing the tree collection, FOBS co-founder and board member Mary Knoll said. The funding will help pay for programs, projects, supplies and equipment for FOBS’ after-school program, she said.