Scientists agree that large woody debris in rivers is critical for fish, including the spring chinook, listed as “threatened” under the federal Endangered Species Act.

About one hundred years ago, development eliminated much of the Stillaguamish River delta’s nearshore habitat - areas that sustained chinook salmon and other species that depend upon estuaries to survive. Dike construction eliminated much of the delta’s complexity, diminishing the quantity and quality of fish habitat. The key missing element, experts say, is wood.

“Wood is absolutely essential for the health of habitat like this,” said Pat Stevenson, the tribe’s environmental director. “Depositing large logs like this makes it more likely that additional wood will be recruited and stay in the river delta, which can only help the ecosystem.”

Historically, logjams occurred naturally, improving ecosystem conditions. Currently, when today’s smaller trees fall into the river, without bigger logs to hold them in place, they are simply swept out to sea.

Without natural logjams, today’s driftwood also washes through the intertidal area, leaving a largely featureless plain devoid of worthwhile habitat. Wood creates pools where salmon can rest and cover that helps young fish hide from predators.

“Strategically placing these logs will, we hope, provide anchoring for other logs and driftwood,” said Stevenson. “Having significant amounts of wood near the river mouth will also help create salt marsh habitat in the river delta.” Salt marsh habitat is critical habitat for salmon as they make the transition from fresh water to salt water.

Besides its habitat value, the project will also serve as a feasibility study for future efforts of this nature.

“The results we see will tell us a lot about how effective using helicopters to create wood structures can be,” said Stevenson. “If this approach works, it would represent an inexpensive alternative to building logjams the conventional way.”

Habitat restoration in the Stillaguamish Basin is desperately needed in these intertidal areas that salmon use to prepare for their journey out to sea. In these nearshore environments, pile-driving barges can only work periodically, because changing tides can prevent access. Using a helicopter rather than a conventional pile-driving barge could bring time and cost-savings benefits.

To assess the project’s effectiveness, the tribe will monitor the area over the next several years to document the anchor logs’ ability to recruit and retain wood. The Stillaguamish Tribe is funding the project; the logs themselves were donated by Pilchuck Tree Farm in Stanwood.

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For more information, conact: Jeff Shaw, Northwest Indian Fisheries Commission, 360.424.8226. Pat Stevenson, Stillaguamish Tribe, 360.435.2755, x 27.