ELLYSON, WILLIAM J. T.* AND STEPHEN C. SILLETT. Department of Biological Sciences, Humboldt State University, Arcata, CA 95521. - Epiphytic Bryophytes and Llichens on Sitka Spruce Trees in an Old-growth Redwood Forest.
Old-growth redwood forests represent an extreme in the realm of forest
ecology. Their canopies reach extraordinary heights (over 110 m), and
individual trees can live for more than two millennia. Ferns, shrubs,
and even trees are abundant as epiphytes on large branches of enormous
redwood trees. However, these trees do not generally support a diverse
and abundant flora of lichens and bryophytes, presumably because their
bark peels easily away. In contrast, Sitka spruce, the second largest
tree in redwood forests, harbors such non-vascular epiphytes in
staggering abundance. Until now, no one has described the assemblage
of epiphytic lichens and bryophytes on Sitka spruce. Using rope
techniques for canopy access, we have conducted a floristic survey of
five tall Sitka spruce trees in Prairie Creek Redwood State Park, CA.
We have quantified the distribution and abundance of all non-vascular
epiphyte species by sampling a fixed proportion of each tree’s total
branch and twig surface area. Biomass estimates were extrapolated to
tree totals. Results reveal a high diversity of lichens, including
abundant cyanolichens (especially Lobaria pulmonaria) in the
upper and outer portions of tree crowns. Thick mats of mosses and
liverworts dominate large branches lower in the crowns.
Key words: Picea sitchensis, biomass, bryophytes, lichens, non-vascular epiphytes, Old-growth redwood forest canopy