While the Lower Elwha Klallam Tribe has been working diligently to protect salmon and their habitat in the Elwha River watershed, there’s another aspect of the pre-dam removal that is just as important: controlling invasive plants.
“These plants quickly spread, preventing native plants from thriving,” said Mike McHenry, the tribe’s habitat manager. “It’s bad for the existing river habitat and if it’s not taken care of, there could be bigger problems after dam removal.”
For the past five years, the tribe’s revegetation crew has been working throughout the river valley identifying and removing invasive plants, such as Scotch broom, knotweed, canary grass and sweet peas.
“This spring alone we’ve treated 10 acres of Scotch broom with herbicide,” said Floyd Cooke, the crew’s field supervisor. “But that’s just barely scratching the surface.”
The tribe has also planted more than 20,000 native conifers and deciduous trees, including douglas fir, western red cedar, grand fir, red alder, black cottonwood, big leaf maple and sitka willow.
In addition to up and down the valley, the tribe’s revegetation efforts have also focused around manmade lakes Aldwell and Mills, which are reservoirs. The biggest concern is what the reservoirs are going to leave behind after they are drained following dam removal.
“Everything that drains into those reservoirs right now might carry invasive seeds,” McHenry said. “Taking care of the plants now surrounding the dams will help prevent their further spread.”
McHenry is also working with the Olympic National Park on a re-vegetation plan for the reservoirs after they are drained.
“After the water is gone, we want that area to be a floodplain forest that will accelerate recovery and habitat forming processes as well as preclude non-native weeds from establishing,” McHenry said.