This thesis includes four separate studies. The first two studies assessed edge effects in a
700-year-old forest. After 20 years of exposure, epiphyte assemblages on the clearcut edge
were similar to those of the forest interior, but there were some differences in vertical
distribution patterns. Several species restricted to the upper canopy of the forest interior
occurred farther down in the crowns of trees on the clearcut edge. Many species were
associated with thick moss mats. Thalli of two cyanolichen species were reciprocally
transplanted among four tree crowns. Lobaria oregana grew less on the clearcut edge than
in the forest interior. Populations of Pseudocyphellaria rainierensis had acclimated to the
edge environment. The third study evaluated whether these two species require old growth
and/or thick, underlying moss mats to achieve normal rates of growth and mortality. Thalli
were transplanted into tree crowns in 13 forest stands representing 4 age classes: old
growth, mature, young, and recent clearcut. Wooden racks were used instead of trees in
clearcuts. Half of the cyanolichen thalli were transplanted onto thick moss mats, half onto
bare bark. Both species grew at least as well in the younger forests as they did in old
growth, but growth rates were significantly lower in clearcuts. Mortality rates were very
low in young, mature, and old-growth forests but high in clearcuts. P. rainierensis grew
significantly better on moss than bare bark. The fourth study evaluated the long-term
potential of live tree retention for cyanolichen conservation. Lichen litterfall was sampled
in a natural, multiple-age stand containing remnant trees and regenerating forest. Two
lichen species (L. oregana and Sphaerophorus globosus) were strongly associated with
remnant trees. Biomass of both species was highest near remnant trees and was
significantly higher within groves of remnant trees than at the edges of these groves or near
isolated trees. Cyanolichen populations appear to have persisted on remnant trees since
before the last fire. They are slowly recolonizing the regenerating forest. Retention of live
trees, including hardwoods, combined with longer rotation periods, has great potential to
maintain cyanolichens in managed forests. / Graduation date: 1996
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34625 |
| Date | 22 November 1995 |
| Creators | Sillett, Stephen Charles |
| Contributors | McCune, Bruce |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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