Snag Boat Bend Floodplain Reforestation - The Final Frontier

The project is located near river mile 145 on the Willamette River south of Peoria at Snag Boat Bend, which is a unit of William L. Finley National Wildlife Refuge owned and managed by the US Fish and Wildlife Service (USFWS). Historic floodplain forest has been converted to farmland, and aquatic and terrestrial weeds threaten off-channel habitat and existing floodplain forests. Floodplain forest will be re-established or enhanced in this project. The understory of mature cottonwood forest has been heavily invaded with invasive, non-native plants, eliminating recruitment of young native trees and shrubs and endangering the long-term health of the stand. Management of non-native vegetation is underway and native trees and shrubs will be planted in its place during the proposed project. Former blackberry monoculture will be replanted with native trees and shrubs, with the goal of establishing cottonwood-maple-ash forest. Finally, young cottonwoods planted by USFWS in the early 2000s, were overstocked, resulting in a dense cottonwood overstory with no understory or ground cover, except for pockets of non-native weeds. Thinning and non-native vegetation management is underway and the proposed project will establish native vegetation in the understory. The work will improve habitat for 12 Oregon Conservation Strategy species, including upper Willamette River spring Chinook salmon. Plant stewardship activities (reported as C.11 - Site Maintenance) will be conducted for up to five years after the plantings are completed. These stewardship activities, consisting of mechanical and chemical noxious weed control and watering, will ensure the success of the project plantings by helping plants achieve free-to-grow status.

Because the projects scheduled end date is after the PCSRF FFY 2019 award closes, no funds allocated for this project are reported as match to PCSRF funds.

The proposed project lies almost completely within the 2-year inundation zone. As shared during the virtual site tour, we observed juvenile UWR spring Chinook using flood channels within the project area in early 2020. These flood channels are nearly 100% occupied by reed canarygrass currently. The project area is clearly used as refuge habitat during high flows. Native vegetation will offer more diverse cover for native fish and also offer other food web benefits due to more diverse fruit/seeds/nuts, pollinator resources, and insect associations. Our proposed work will add complexity to the floodplain and increase the quality of this refuge habitat. Establishing overstory trees will help reduce the rate of warming in the Willamette River, which will benefit both juvenile and adult Chinook using the river downstream of the project area. Trees established along the Willamette River during the project will contribute organic matter to the river, helping to fuel the aquatic food web, and will also eventually become large woody debris in the river that will improve habitat complexity, benefiting Chinook and other native fish.
Restoring fluvial processes at the Porter Dam site will help improve the overall ecological function of the Snag Boat Bend property and, in concert with the proposed reforestation, allow it to offer multiple benefits to all age-classes of important fish and wildlife species in close proximity.