Prior to 15N addition on 1-Jul-2003, green leaves and parts of mosses (for Sphagnum spp, both red and green parts were included) of the dominant species were collected from areas adjacent to the 15N addition plots (3m x 6m). After the 15N addition, the same tissues were collected from within the plots 1 and 2 yr later. Within 12 hrs of collection, plant samples were separated by species and tissue type and were dried at 50ºC.

Prior to post-15N addition sampling, multiple band-transects (each transect = 1m x 6m) were established directly below each labeled plot. The transects ran perpendicular to the hill slope with the upper side (i.e., a side closer to the crest) of each band-transect located at 1, 5, 10, 13, or 15 m from the lower side (i.e., a side closer to the creek) of the labeled plots. Plant samples were taken from >5 randomly selected spots within the plot or transect and combined by plot or transect prior to sorting.