Peck,
J.E. & P.S. Muir. 2001. Harvestable epiphytic bryophytes and their accumulation in central
western Oregon, The Bryologist 104(2): 181-190.
Methods for characterizing the composition,
biomass, and accumulation rates of harvestable epiphytic bryophytes in the
understory of temperate forests have recently been developed, but have yet to be
implemented in a much wider geographical area and adapted to provide estimates
at the individual mat level. In response to regulatory need, we modified
and implemented these methods in 27 50+ yr-old upland and riparian forest stands
below 915 m to: a) characterize the composition of harvestable
epiphytic bryophytes in central western Oregon, b) evaluate the compositional
changes immediately following harvest, and c) retrospectively estimate minimum
simple accumulation rates for harvestable bryophyte mats. Twenty-two bryophyte species, two lichens, and one vascular plant were
found in a total of 433 sampled mats, dominated by Isothecium myosuroides,
Neckera douglasii, Antitrichia curtipendula, Frullania
tamarisci subsp. nisquallensis, and Porella navicularis.
Harvest brought on significant shifts in the relative abundance of species
primarily through the disproportionate removal of these species, which are
commonly found in harvestable bryophyte mats throughout western Oregon. The minimum simple accumulation rate for bryophyte mats from 13 of these stands,
calculated as the oven-dried mat mass per unit surface area divided by the stem
age, was 22.4 (std. 15.5) g/m2/yr and is approximately comparable to
that previously observed in the Coast and Cascade Ranges of northwestern
Oregon. This accumulation rate translates into a commercial harvest
rotation period of at least 21 (std. 12) yrs. This long rotation time,
coupled with the scarcity of sites supporting harvestable mats, leads to our
recommendation that commercial bryophyte harvest be prohibited in the study
region.