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 wollastonite 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.  The percent cover of spring ephemerals will be recorded every May 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, but a few years later, the herbaceous layer is still adjusting to the increased light level at the forest floor.  As a result, percent cover of some spring herb species, such as Erythronium, increased from 1998 to 1999.  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 May 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.  As of 2000, casual observation indicated that most pellets fell into the litter layer where they were protected from rain, and had not yet dissolved.  In 2001, undissolved pellets were much less obvious, and they were rarely seen by 2003.

        Large year-to-year differences may be due in part to the timing of spring surveys. Spring weather conditions can make the date of emergence and flowering of each species unpredictable. For instance, the 2002 survey was conducted one week earlier than in previous years, and although Erythronium was at peak flowering, Uvularia foliage had not yet unfolded, while many Trillium stems had been broken off by snow a few days prior to the survey. The permanent plots will be surveyed again in July of 2004 and for several seasons to come to continue monitoring changes.

Cover percentages by species:     Harvest plots  Permanent plots    1998  1998  1999  2000  2001 2002 2003 2004 Watershed 1 Erythronium 5.37  3.56  9.21  6.40  5.04 2.91 4.88 3.50 Uvularia 1.77  1.27  1.34  0.72  2.53 0.28 0.56 0.53 Trillium erectum 0.23  0.26  0.33  0.25  0.36 0.14 0.16 0.21 Watershed 6 Erythronium 3.96  3.43  10.33  8.18  5.72 3.43 5.04 4.23 Uvularia 0.10  0.11  0.07  0.09  0.23 0.02 0.04 0.07 Trillium erectum 0.40  0.19  0.21  0.21  0.22 0.10 0.12 0.13

2. Plant chemistry:

        "Grab" samples of several species of spring ephemerals have been collected on Watershed 1 over the past several years.  The aboveground portion of these plants were collected separately for  three or four different zones within the watershed.  Collection was not quantitative, but achieved by walking over the entire area and grabbing plants here and there.  Samples were dried, ground in a Wiley mill, ashed at 500 degrees C, dissolved in a nitric acid solution, and analyzed on an ICP spectrometer for several elements.  In the graph below, the values from each of the three or four zones within the watershed were averaged, with error bars representing standard deviation.  In 1998, collections were done in June, while in 1999 they were done in May.  To tease out differences that result from different collection times, two collections were done in 2000--one in May and one in June.  The results from these two post application collections are plotted against the 1998 pre application collection (June) and the 1999 pre application collection (May).  May collections were conducted in 2001, 2002 and 2003.  Notice that calcium concentrations are generally higher in June than in May.  Calcium concentrations appear to have increased slightly in Uvularia relative to pre application levels by June 2000, in Trillium by May 2001, and in Erythronium by May 2003.

Web page created May 2000
by Ellen Denny