1997c. Commercial Moss Harvest Impacts:
A retrospective study.
Report to the Tillamook Resource Area, Salem District Bureau of Land Management,
The impacts of commercial moss harvest on bryophyte communities has only recently begun to be documented. This represents the first attempt to compare sites known to have been commercially harvested with those believed to be undisturbed for at least 20 years. Seven pairs of 1/3 acre plots in the Tillamook Resource Area were surveyed for the most common and abundant epiphytic bryophytes. Plots were compared on the basis of average cover and total species richness across all available substrates for trees and shrubs (by species) , logs, and the forest floor. No differences among treatments were detected for cover, species richness, or species composition for the most common and abundant epiphytic bryophytes on any substrate. The failure to detect differences may be due to a) the general nature of these surveys, which are not sensitive to rare species and/or b) the likelihood of previous disturbance in the "unharvested" plots. Although "unharvested" plots were selected on the basis of our best understanding of what these areas should look like, the absence of any sites that are truly known to be undisturbed leaves us without a standard for comparison. Application of these results to other areas of the Resource Area is not recommended, given site selection criteria, the focus on only common and abundant species, and the unknown disturbance histories of these plots.
PNW Moss Lit