In the spring of 1998, we installed 100 permanent 1 x 1 meter herb plots on both Watersheds 1 and 6 in preparation for a calcium addition experiment on Watershed 1.  Percent cover of herb, shrub and tree species was recorded for each plot in the spring and summer of 1998 and 1999, before the addition.  Wollastonite was applied by helicopter in October 1999, and the percent cover of summer herbs subsequently recorded every July and compared to the pre application results.  A parallel set of "harvest" plots was destructively sampled in 1998.  Percent cover for these plots was also recorded in 1998 and is included in the data below.  Plant chemistry is also being monitored for changes resulting from the wollastonite addition.

        1. Herbaceous cover
        2. Plant chemistry
 
 
 

1. Herbaceous cover:

        The ice storm of 1998 occurred before the plots were established, and the herbaceous layer is still adjusting to the increased light level at the forest floor.  As a result, percent cover of some herb species, such as Dryopteris, increased from 1998 to 1999 and again from 1999 to 2000.  Watersheds 1 and 6 have very similar degrees of canopy damage, so we would expect a similar increase in cover for both watersheds.

        As of mid July 2004, however, there was no apparent increase of herbaceous cover on Watershed 1 as compared to Watershed 6 as a result of the wollastonite addition.  The permanent plots are no longer surveyed for herb cover.

Cover percentages by species:     Harvest plots Permanent plots   1998 1998 1999 2000 2001 2002 2003 2004 Watershed 1 Dryopteris 5.83 4.88 5.98 7.19 6.46 5.92 5.51 5.13 Oxalis 0.57 0.42 0.56 0.54 0.62 0.51 0.42 0.49 Uvularia 0.81 1.26 1.66 2.33 3.01 2.59 2.04 2.38 Lycopodium lucidulum 0.81 1.32 1.28 1.01 0.94 0.80 0.67 0.66 Maianthemum 0.31 0.28 0.44 0.56 0.51 0.61 0.49 0.38 Dennstaedtia 0.42 0.21 0.56 0.83 0.65 0.26 0.19 0.15 Clintonia 0.26 0.27 0.25 0.34 0.33 0.30 0.28 0.19 Aralia 0.21 0.39 0.52 0.67 1.03 0.76 0.71 0.55 Watershed 6 Dryopteris 5.65 4.33 7.41 8.82 8.77 6.58 6.13 6.42 Oxalis 1.54 2.50 2.84 2.59 3.09 1.35 1.06 1.44 Uvularia 0.16 0.10 0.19 0.31 0.35 0.31 0.16 0.17 Lycopodium lucidulum 1.53 1.42 1.25 1.25 1.09 0.83 0.73 0.42 Maianthemum 0.80 1.04 1.05 1.67 0.85 1.64 1.17 0.95 Dennstaedtia 0.24 0.44 1.15 1.41 1.13 0.87 1.14 1.24 Clintonia 0.86 0.86 0.79 1.40 1.30 1.16 1.71 1.00 Aralia 0.06 0.04 0.08 0.04 0.10 0.04 0.05 0.04

2. Plant chemistry:

          "Grab" samples of wood fern (Dryopteris spinulosa) have been collected on Watershed 1 during the first half of July starting in 1996.  This fern is the most abundant of the herbaceous species on the watersheds and comprises 90% of the herb biomass. The fronds of these plants were collected separately for four different zones within the watershed.  Collection was achieved by walking over the area of each zone and grabbing single fronds from individual plants here and there which were pooled into 3 samples for each watershed zone.  Samples were dried (80^o C), ground in a Wiley mill (2 mm screen), ashed at 500^o C, the ash dissolved in a nitric acid solution (50 ml final volume), and analyzed on an ICP spectrometer for several elements.  In the graph below, the values from each of the four zones within the watershed were averaged, with error bars representing standard deviation.

       Calcium concentrations appear to have significantly increased in wood fern fronds relative to pre application levels.  Averaged over all elevations, concentrations have increased by about 65% between 1999 and 2000, following the calcium addition.  Before the addition, W1 ferns had a similar calcium concentration to ferns from a non-treated area west of W6, where a long-term fern collection has been conducted since 1985.  We will continue to monitor the tissue chemistry of ferns in W1 and in the non-treated area west of W6 to see how this pattern develops over time.

Web page created November 2000
by Ellen Denny and Tom Siccama