After seven years of planting, weeding and seeding, the Lower Elwha Klallam Tribe has finished revegetating the Elwha River valley and will let Mother Nature mostly take over.
“We’ll continue supplemental planting as needed, and we’ll treat invasive plants as we monitor the area,” said Kim Williams, the tribe’s revegetation field supervisor. “But as the native plant communities mature, they will help push out weeds.”
As part of the Elwha River restoration project, and in partnership with Olympic National Park, revegetation crews have been removing invasive plant species since 2011 when restoration started, plus they planted more than 322,000 native plants and spread about 6,400 pounds of native plant seed.
“The goal has been to increase diversity of plant life, create more plant cover and kind of jumpstart the plant life that may lead to forests in the future,” said Laurel Moulton, assistant manager at the park’s Matt Albright Native Plant Center in Sequim. Most of the vegetation for the restoration project was germinated and grown in the nursery.
Prior to the removal of the river’s two fish-blocking dams in 2011, and every year since, most of the native seeds and cuttings collected from within a 5-mile radius of the Elwha River were germinated and grown at the park’s plant center for about two years. The plants were then transferred to the old lake beds that were drained as part of restoration.
The crew planted 20 different herbs, shrubs and trees in the two lake beds, including willow, cedar, river lupin, red alder, black cottonwood, Nootka rose, serviceberry and thimbleberry.
There are also areas where young alder, cottonwood and willow trees have grown on their own, Moulton said.
To keep invasive plants under control after the lake beds were drained, crews conducted ground surveys and treated invasive plants with an EPA-approved aquatic-safe herbicide, resulting in a significant reduction in invasive plants, Williams said.
Park crews also established nearly 100 plots to monitor vegetation cover over time.
“These plots have shown an increase in plant diversity, and at the same time, a steady reduction of the exposed ground,” Williams said.
A tree seedling emerges at the Matt Albright Native Plant Center in Sequim, where thousands of trees, plants and shrubs were germinated and grown before being planted in the Elwha River valley. Photo: Tiffany Royal