Seward Park is celebrated by Seattleites for its lush forest dominated by native plant species like sword fern. In autumn of 2013, park visitors noticed sword ferns dying on the south side of the Hatchery Trail. By July of 2014, the stand of dense sword ferns (about a 1/4 acre in size) was more than 90% dead, leaving bare ground. In subsequent years, the decline has spread substantially through the park.
Sword ferns are now dead in a 15-acre area (about 10% of the old-growth forest in the park) and in isolated patches across Bailey Peninsula. Unfortunately, other sites with declining fern populations have been identified in Western Washington and British Columbia.