Experimental planting at Seward Park

In February we planted three lines of young sword ferns, twelve ferns in each line.  These ferns were part of our annual generous allotment of three hundred restoration plants from Seattle Parks and the Green Seattle Partnership.  They come from regional native plant nurseries; the plants are about two years old. 

Two of these lines are in the original ground zero at Seward Park, an area that has been barren now for three years, with no natural regeneration of any species.    The third line is about fifty yards north and just outside of the current boundaries of active die-off.   Every fern was "watered-in".  Half of them - every other fern in each line - were infused with mycorrhizal spores.

I hypothesize (based on evidence presented in the next blog post "A Lazarus Fern?") that the likely pathogen responsible for die-off has swept through ground zero and is no longer present.  Thus I predict that the two lines of twelve ferns in ground zero, if we water them through the first summer or two, will mostly survive.  As the die-off zone spreads it will soon encompass the northern line of twelve ferns.  I predict that most of these twelve ferns will die.    More specifically, and as a nod to statistical rigor, I predict a p-value < 0.05 when, after five years, we compare the survival rates at the two contrasting sizes, ground zero (24 ferns) and the northern line (12 ferns, aka AD for "active die-off).  Here this is mocked up in a little R code:

set.seed(17)

GZ <- as.integer(runif(24) + 0.7)       #   75% survival: 0 1 1 1 1 1 0 0 1 0 1 0 1 1  
                                                           #                           1 1 1 0 1 1 1 1 1 1 

AD <- as.integer(runif(12) + 0.25)    #   25% survival: 1 0 0 0 1 0 0 0 1 0 0 0

t.test(GZ, AD)$p.value                      #   0.0047

I photograph all thirty-six ferns every week and will create a time-lapse video for each fern as these weekly photos accumulate.  The two GZ lines are shown in the picture above.