The dynamics of stands in the mid-elevation old-growth
Douglas-fir (Pseudotsuga menziesii) forests of the central western
Oregon Cascade Range were investigated using stand structure
analysis. Trees with different growth rates were commonly present
in the same stand, which resulted often in a weak correlation
between tree diameter and age. Thus,...
Lichens are an important part of the biota in western Oregon forests, where
they perform valuable ecological roles and contribute significantly to biodiversity.
Lichens in western Oregon are threatened by a number of factors including air
pollution and land use practices. If we wish to maintain the persistence of lichens...
I surveyed epiphytic macrolichens and bryophytes in six stands in each of seven riparian stand types in the Oregon Coast Range. This study (Chapter 2) describes the association of epiphytes with stand types and the corresponding potential of forest canopy conversions to affect epiphyte communities. Species composition, diversity, and representation...
The diverse lichen flora of the Pacific Northwest is being impacted by
population growth and by forest management practices. Accumulating information
about our lichen flora will improve our conservation strategies. This dissertation first
collects information to improve our understanding of how lichen communities vary
among forests of differing structure, and...
Epiphytic, planktonic and benthic diatom assemblages were investigated in Netarts Bay, Oregon. Samples were collected for a
one-year period from February 1980 to March 1981. A planktonic flora was observed only during periods of offshore enrichment when marine neritic species were abundant and were transported into the bay by tidal...
Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season potato varieties Russet Norkotah and Russet Nugget (San Luis Valley only). The experiments were located in the San Luis Valley in Colorado,...
The Pacific Northwest (Oregon and Washington in the United States and British Columbia in Canada) is one of the major producers of red raspberry (Rubus idaeus L.) and blueberry (Vaccinium corymbosum L.) in the world. The expansion of growing area with these crops has resulted in the emergence of new...
Phacelia capitata Rruckeberg is a member of the
Phacelia magellanica polyploid complex (species group
Magellanicae), a group of wide-ranging, polymorphic
perennials in western North America related to the South
American P. secunda (= P. magellanica). The purpose of
this project was to determine, to the extent possible, the
interrelationships of...
Phytophthora root rot decreases availability and quality of rhododendrons produced in the USA. Symptoms of Phytophthora root rot include root necrosis, leaf chlorosis, stunting, and permanent wilt. The purpose of this thesis was to better understand the impact of root damage, soil moisture, nitrogen fertilizer application, and pathogen species on...
Sudden Oak Death (SOD) is a forest disease caused by the oomycete pathogen Phytophthora ramorum, and infects trees in the Western United States and Europe. This generalist pathogen can infect over 130 species of plants, and causes rapid mortality in tree species in the Fagaceae. Sexual reproduction is thought to...