Table of Contents

Tuesday, March 14th,  2017

Table of Contents

Introduction

The Ntirogen Deficiency Hypothesis

Individual sword ferns apparently live for centuries

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)

Nitrogen Deficiency Hypothesis revisited (assay #3)

The nitrogen deficiency hypothesis* gets some highly tentative support from my work this week (March 4-11 2017).  “Not yet shown to be a dumb idea” - that’s how I’d put it.  These results may justify followup work:  more samples in a good experimental design, rigorous sample prep, laboratory assays by someone who really knows what they are doing.

[*The hypothesis:  by 200 years, a fir/hemlock/cedar forest needs a new nitrogen source, with early succession nitrogen fixation exhausted.   Lobaria oregena is reported to perform this role in the Andrews Experimental Forest; salmon (abetted by flooding and predation) in BC and Alaska.  References on request.   Without lobaria - which is reported to be sensitive to pollution - and in the absence of salmon predation (no bears), the old-growth forest at Seward Park may be experiencing a deficiency of available nitrogen.  Perhaps this is most dire at Ground Zero.  Perhaps this weakened the sword ferns.  Perhaps an opportunistic pest (phytophthora,  thrips) gained a foothold.  Lots of as-yet unsupported conjecture from me here.]

This time around, my third round of sampling, I:

1. divided each vertical 6-inch soil core into four segments each ~1.5 inches in length
2. dried the samples for a week indoors at room temperature
3. pulverized the dry soil, creating fine soil particles
4. used two positive controls: freshly purchased potting soil, with and without nitrogen fertilizer added

The color-code:

   

Potted soil samples (unfertilized on left, fertilized on right):

Three field samples:

1) 50’ east of the Jobox in second growth forest, across the upper loop road (south) from the sqebeqsed trail entrance, between two large red alder trees, at successive 1.5 inch depths, surface to depth.  I see faint red in sample 1 (perhaps), in sample2, maybe also in sample 4.

2) Ground Zero, central site #1. I see faint red in sample 1, none in sample 2-4. 

3) Ground Zero, slightly west of center, site #2.  I see no red here at all.