Table of Contents

Introduction

Monthly Precipitation Records 2010-2016

Informal Notes on Weather Extremes & Sword Ferns: California vs. Seattle, Annual Precipitation Records

Reports from the Pittermann Lab at UCSC: Sword Ferns & Drought

Three West Coast Fern Biologists Offer Insight and Knowledge: Drs. Smith, Wagner and Burns

Narrative Summary (including comments from NY Botanical Garden’s fern curator, 

  and world expert genus taxonomist  from the University of Vermont)

January 10 2016:  more die-off found in the northwest corner of Seward Park (with video)

December 27 2016: die-off on Mercer Island's Upper Luther Burbank Park  (with video)

Paul Talbert: Comments on PCR Results 

WSU Puyallup Phytophthora PCR Results 

Novermber 13: a presentation to the Washington Native Plant Society, by Dr. Tim Billo and undergraduates Kramer Canup and Tristan O'Mara 

September 22: Grant Proposal to the Bullitt Foundation 

Informal final report from UW’s Tim Billo and his two undergraduate students
to the Seattle Parks Field Committee (June 2nd, 2016)

Lab report from Dr. Marianne Elliott, WSU

LSU Professor Valverde, plant pathologist, 2008 paper on “new virus causing disease in [a related] fern”

Site visit by WSU pathologists, and the “introduced phytophthora” thesis

PCR and Sequencing for Pathogen Detection (July 25th, 2016)

Monthly Precipitation Records, 2012-2016

Looking for a weather/die-off correlation in monthly reports: we do not know if ferns are resilient against pronounced summer drought and heat in years of average (or better) rainfall.  Nor do we know yet if  extreme-but-only-in-summer weather is what we have actually had. As a first step towards assessing that, here are the monthly records from SeaTac airport.

It may be that near zero rainfall in some summer months (in contrast to the average summer montly rainfall of one inch) over repeated and nearly consecutive years, takes a toll.  We see such summers, with two bone-dry months in 2012 and 2015.  2013 had one dry month.

Perhaps the strongest argument against the weather hypothesis, in which weather is the driving cause, if not the proximal cause, is that most of the sword ferns in Seward's old-growth forest are in good health.   The die-off is three years-old, spreads radially uphill and down, now occupying 5 acres (completely dead) and >20 acres (the total affected area).