UW-Restoration Ecology Network

West Duwamish Greenbelt

At over 800 acres of forested public land, the West Duwamish Greenbelt is the largest remaining contiguous forest within the city of Seattle. The greenbelt runs for over four miles along the length of a steep hill slope over the Duwamish waterway. It is dominated by forests regenerating following logging during the past century.

2003 - 2004 | 2004 -2005 | 2005 -2006

2005 - 2006
Project name	West Duwamish Greenbelt Restoration Project
Location	South Seattle
Client	The Nature Consortium
Students	H. Heinrich (UW Seattle; Environmental Science and Resource Management), S. Martin Sprenger, J. Wood, B. Castle, K. Dooley, J. Naas (UW Seattle; Master of Urban Planning and Master of Public Administration)
Site description	The project is 2 acres of upland forest and riparian habitat within the West Duwamish Greenbelt on the West Marginal Hillside. The West Duwamish Greenbelt forest is a seond and third growth forest consisting mainly of bigleaf maple, alder and cottonwood, with very few native shrubs. There is a small wetland onsite and two streams that run into culverts under West Marginal Way.
Restoration challenge	Clients wished to remove non-native species and plant natives. Declining forest health and a lack of plant diversity are concerns. Hillside erosion is a problem; planting native trees and understory will help keep soil in place.
Restoration approach	The primary goals were to control invasive species, reintroduce and enhance habitat conditions for native vegetation and wildlife, and stabilize the existing slopes on the site while working with local community members. The students removed non-native species and added mechanical barriers and mulch to retard recolonization. Native trees, shrubs, grasses, and herbs were added with a focus on species to rapidly colonize the site to control reinvasion by non-native species. Install woody debris to increase structual diversity and possibly increase invertebrate populations. Create a buffer around the site for expansion purposes and involve and educate the local community about the restoration goals for the site.

2004 - 2005
Project name	West Duwamish Greenbelt: forest restoration
Location	South Seattle
Client	The Nature Consortium, City of Seattle Parks Department
Students	W. Chung, B. McMeekin (UW Seattle; Environmental Studies), L. Mazzola (UW Seattle; Education), S. Rosebrough (UW Seattle; Civil Engineering), S. Stolnak (UW Seattle; Fisheries), C. West (UW Seattle; Environmental Planning)
Site description	an area of approximately 350 sq. meters, including upland slopes and a depressional wetland pocket. It is located in a power line utility corridor positioned between two previous Nature Consortium-sponsored restoration projects. Site was mostly open canopied and was dominated by Himalayan blackberry. Slope gradient on the site ranges from flat in the wetland area through approximately 40 degrees on the open slope below the power lines to nearly vertical on the west edge of the wetland. The site also has a small stream whose banks were dominated by reed canary grass.
Restoration challenge	Clients wished to remove non-native species and plant natives, connecting two other restoration projects. The species planted had to be effective at outcompeting native plants, while not growing too tall as to interfere with the power lines. The site’s steep slope presented an additional challenge of limiting erosion while working to restore the site.
Restoration approach	The primary goals were to control invasive species, reintroduce and enhance habitat conditions for native vegetation, and stabilize the existing slopes on the site while working with local community members. The students removed non-native species and added mechanical barriers and mulch to retard recolonization. Native trees, shrubs, grasses, and herbs were added with a focus on species to rapidly colonize the site to control reinvasion by non-native species. The upper slopes were stabilized using bioengineering techniques including install stakes and bundles of native plant material, and using biodegradable landscape fabric and woody debris found on site.

2003 - 2004
Project name	West Duwamish Greenbelt: forest restoration
Location	south Seattle
Client	The Nature Consortium, City of Seattle Parks Department
Students	J. Simpson, C. Coen (UW Tacoma; Environmental Science), J. Keith (non-matriculated)
Site description	a 2-acre forested slope dominated by early-successional native deciduous trees and a low diversity understory of mostly non-native English Ivy. Open patches were infested with non-native species such as Himalayan blackberry and in wetter sites, reed canarygrass. The site also has a small stream whose banks were dominated by non-native species.
Restoration challenge	Clients wished to remove non-native species and promote succession toward mature native evergreen forest communities characteristic of this region. Increasing instream physical habitat and stabilizing streambanks were also important goals.
Restoration approach	UW-REN students, working with local community members, removed non-native species and added mechanical barriers and mulch to retard recolonization. Native trees, shrubs, grasses, and herbs were added with a focus on species to (1) rapidly establish a shade canopy to control reinvasion by non-native species in forest openings and along the stream, (2) promote eventual succession to a mature evergreen forest (implanting of late successional conifers), and (3) create structural diversity in the stream channel and with vegetation along the stream for habitat. Bioengineering with native plants was used alongside woody debris to stabilize the streambank.