The Suquamish Tribe’s Doe Kag Wats estuary is the site of a large woody debris removal experiment this summer.
”Our hypothesis is that by removing the excess amount of the milled and treated logs that have washed into the estuary, the native marsh vegetation will be restored, as well as insect species, many of which are important to both healthy and recovering salmon populations,” said Tom Ostrom, the tribe’s salmon recovery coordinator and project manager.
The project is two-fold: First, the tribe and the state Department of Natural Resources removed the remaining creosote pilings from the estuary. These toxic pilings have been pushed into the estuary by storms and tides for decades.
Nearly 300 tons of creosote pilings were removed by helicopter, with the help of two Washington Conservation Corps crews. More than 50 small piles of contaminated wood were prepared for helicopter pick up; crews then worked in the helicopter drop zone to cut the wood into smaller pieces for disposal.
The second project involved sectioning off a small pilot area of the estuary to monitor how the marsh responds ecologically after removing the accumulation of anthropogenic wood (wood that has been cut into long, straight logs).
This wood easily floats and rolls around the estuary at high tide, crushing and shading vegetation while silt fills marsh channels, said Paul Dorn, the tribe’s senior research scientist.
Natural wood, with its attached root wads and branches, is far less abundant and less mobile, resulting in a greater abundance of vegetation – the base of the food chain. A dozen anthropogenic logs within the estuary were chained together to create a triangular area, where vegetation and insect recovery, plus possible use by fish, will be studied.
Students from Western Washington University’s Huxley College of the Environment and the tribe’s Chief Kitsap Academy will be involved with the monitoring and data collection for five years. Design firm Coastal Geologic Services designed the project and will lead the monitoring.
“Wood is a critical component of estuaries but this may be an instance of too much of a good thing,” Dorn said. “Many of our freshwater streams could use this wood as habitat and stream structure. In an estuary, this anthropogenic wood may be diminishing productivity.”