The Die-off Jumps the sqebeqsed trail

Over the last three years our attention, and our monitoring efforts, have been mainly upon the southeast sector of the Magnificent Forest, south of the Hatchery Trail, east of the sqebeqsed trail.

On an evening walk in the woods on Wednesday (5 April 2017) I was surprised and alarmed to see many instances of new brown sword fern crown stumps within a few hundred feet of ground zero, on the west side of the sqebeqsed, on the Andrews Bay Trail.  See map below.

This new discovery, along with our current pessimism about identifying the cause of the die-off, and the two informally validated new sites (Suquamish Sandy Point on the Kitsap Peninsula, Upper Luther Burbank Park on Mercer Island), triggered a state change in my assessment.

Which is that the die-off will likely continue to propagate through the Magnificent Forest in semi-exponential growth - that is, faster than linear, but not so fast as annual doubling.  It is likely therefore, that within ten years all of the sword ferns will be dead or dying.  Furthermore, and for reasons unknown, regeneration is non-existent in all of our die-off areas.  Ground zero has been open for colonization for three years; not one new plant has appeared. (See reference below for possible insight into this "regen problem" based upon 2012-13 research at Lincoln Park.)

There exists, therefore, a grim possibliity:  that a full half of the understory will be destroyed without replacement, disrupting the structure and likely the function of the old-growth forest with unknown but worrisome consequences.

Note that the two other informally validated die-off sites, on Mercer and the Kitsap, ARE regenerating.   Seward is an anomaly in this regard, perhaps due to coarse woody debris removal in the 1960s, and the absence of any of the well-known old forest nitrogen sources.

Seed limitation and lack of downed wood, not invasive species, threaten conifer regeneration in an urban forest  Ailene K. Ettinger,  Benjamin R. Lee, Sarah Montgomery