Good News About Seward Park’s Mysterious Fern Die-Off

by Paul Nelson

For those following the story of the mysterious fern die-off in Seward Park, first reported in the South Seattle Emerald back in August 2017, there is a welcome update.

According to Paul Shannon, the amateur sleuth attempting to solve the die-off mystery, there is a lot of good news. He says:

    1. “Ground Zero is no longer the barren, non-regenerating  slope it was for several years.  In addition, a few fringe cups have sprung up in the first instance of natural regeneration…”
    2. “The Seattle branch of 100 Women Who Care raised almost $8,000 to support research into the cause and nature of the sword fern die-off…”
    3. A successful “beer bottle experiment” suggests that there is a pathogen at work here or, in scientific terms: “some still unknown biotic vector” and not “moisture stress.”

Shannon updated his Seward Park Fern Die-Off Blog on December 2 and added a link to a map of the fern die-off sites in the Puget Sound region.

Shannon reports that Seattle Parks ecologist Lisa Cieko has led a successful response to this situation by planting mixed native species and mulching and watering them over the summer and that 24 sword ferns planted in 2018 have a nearly 100 percent survival rate. There is a grad student from Reed College doing research on the situation and Shannon answered a few follow-up questions from the South Seattle Emerald via email.

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South Seattle Emerald: How did you get the contribution from 100 Women Who Care Seattle?

Paul Shannon: The 100 WWC invite 3 non-profits a year to pitch their cause to them. Any member can propose a non-profit, then I think names are drawn out of a hat to select the three.  Friends of Seward Park was nominated, made it into the round-of-three. Paul Talbert (FoSP president) suggested that the fern die-off could most use the money, so he and I went to the meeting, we made the pitch. We were surprised and delighted to hear the next day that we were selected.


SSE: How did the Reed College student get involved in the project?

PS: The Reed student had a prior interest in sword ferns, googled around late last winter, found Tim Billo’s and my blogs, then contacted Tim.


SSE: Are you saying there is NO LINK to ACD regarding the die-off? (Anthropogenic Climate Disorder/Climate Change.)

PS: We see no direct link to climate.  Many have suggested drought or heat (Seattle Parks favors that view, as does their consultant) but there is no data to support the hypothesis. In fact, significant counter-evidence now exists as you can see on the blog.

An indirect cause is quite possible.  For instance, a well-tolerated pathogen may be newly virulent due to longer, hotter summers. Or an unknown protective commensal organism may be less fit. The pine bark beetle is a case of the former, I believe.

But since the die-off first appeared in 2010 before any statistically significant climate changes in the Puget Lowlands, we do not (yet) see a mechanism.

Slightly more plausible might be an imported pathogen.   There is lots of precedent for this:  eastern hemlocks, 100 years ago for the American chestnut and elms, spotted lanternfly in just the last few years.

We really don’t know.

Featured image: A trail at Seward Park (Photo: Shannon Kringen)