UW News

October 26, 2016

Completed boardwalk trail in Yesler Swamp offers access to wildlife, natural areas

UW News

Yesler Swamp, part of the Union Bay Natural Area along Lake Washington that is managed by UW Botanic Gardens, has a newly completed, fully handicapped-accessible boardwalk trail that loops throughout the wetland, offering opportunities for birdwatching, exercise and a chance to experience nature in the heart of the city.

A segment of the new boardwalk.

A segment of the new boardwalk.Wendy Gibble/UW

Restoration work on the 6-acre swamp began more than 15 years ago as part of a UW capstone course taught by Kern Ewing, a professor in environmental and forest sciences. The swamp was overrun with invasive plants, including reed canary grass and English ivy, and a stronghold of Himalayan blackberry made most of the area impassable.

After mowing down some of the blackberry thickets, Ewing decided to try a less mechanical approach: Plant young, fast-growing willow trees to cast shade on the sun-loving invasives and eventually kill them.

Those initial plantings took hold, grew tall and served as a starting point for robust restoration work. Now, swamp-loving conifers and other native shrubs thrive in the area that has far fewer invasive plants than a decade ago.

“I think people assume a natural area will just heal itself, but in a city, that just doesn’t happen,” Ewing said. “There’s always going to be some restoration needed in Yesler Swamp. It’s great, because we wanted a project that would have an ongoing need, and to involve students in meeting that need.”

Swamps are wetlands with trees, and conifers such as Sitka spruce and western red cedar would have colonized the Yesler Swamp area. Most of Seattle’s original swamps have been logged, drained or filled, and this swamp is one of the only remaining ones along Lake Washington.

“This swamp provides a habitat type that’s rare,” said Zac Mallon, a recent UW graduate who helped with the restoration work. “It provides habitat for wetland birds, migrating salmon and other fish species and amphibians in the Seattle area.”

About five years ago, the swamp’s Laurelhurst neighbors formed the group Friends of Yesler Swamp and began the boardwalk trail project that protects sensitive habitat and keeps walkers’ feet dry when the lake level rises. The boardwalk trail also makes it easier to do ongoing restoration work.

The view from Yesler Swamp.

The view from Yesler Swamp.Wendy Gibble/UW

The group raised more than $400,000 to build the 1,500-foot boardwalk, designed by SB&A Landscape Architects. The UW will now assume responsibility for ongoing maintenance and monitoring restoration work within the swamp.

“It is wonderful that the Friends of Yesler Swamp wanted to take on the trail and boardwalk project,” said Fred Hoyt, interim director of UW Botanic Gardens. “It is providing all-year access for the students to work on projects, learn how to deal with restoration and report to the state agencies. The area is an excellent outdoor laboratory that allows us to work hand in hand with the community on a range of activities.”

Hundreds of students have been involved over the years in work parties and research projects in Yesler Swamp. UW students, local elementary school and high school students have taken their turn at pulling out invasives. A number of UW graduate students also have completed thesis projects using the swamp as a convenient test bed.

An overlook section of the boardwalk.

An overlook section of the boardwalk.Wendy Gibble/UW

“For UW students, this is a place to run experiments, to learn about restoration and to try new things,” said Kat Cerny-Chipman, a UW master’s student in environmental and forest sciences. “It’s a forever project, but since this is a place to learn about restoration, that’s actually OK.”

Henry Yesler’s 1800s-era sawmill used to occupy the land now known as the swamp. After the mill burned down, the UW bought the property in 1927 and it sat for years, accumulating a dense, impassable thicket of invasive plants. Now the land is teeming with native plants, a resident beaver (and dam) and more than 100 bird species sightings.

“Because the swamp was forgotten is why we can have this resource now,” Cerny-Chipman said. “I think the specialness of the swamp is really hard to put into words. I encourage people to get out and see it.”

Yesler Swamp is located on the east side of the UW’s Center for Urban Horticulture. It is free and open to the public.