Four study sites were selected along an altitudinal gradient on Mt. Ashland in the Siskiyou Mountains of southern Oregon. The altitudinal gradient roughly corresponded to a gradient in temperature and water availability ranging from very hot and dry to cool and moist. Air and soil temperatures were continuously measured on...
Snowbrush (Ceanothus velutinus), red alder (Alnus rubra), and
bitterbrush (Purshia tridentata) are three important nitrogen- fixing
nonleguminous species. They commonly grow in association with
commercially important conifers in western United States and conceivably
could be utilized to add nitrogen to forest ecosystems. Nitrogen
15 gas was used to study nitrogen...
Two light sensitive mutants of the green alga Scenedesmus obliquus strain D₃ have been characterized. The photodynamic nature of their sensitivity has been established, the subchloroplast site of photodamage has been investigated, and their noncarotenogenic character has been verified. The two mutants possess several similarities, although mutant L. S. -41...
Herbicides are being used as a tool by forest managers to speed
the restocking of sites where tree seedlings face competition from
grasses for limited moisture, light and nutrients. Retarded growth
or, more commonly, death of the seedlings would occur if a selective
herbicide was not used to control competing...
The research presented in this thesis evaluated the effects of
uranyl (UO₂⁺⁺) upon the absorption of Li, Na, K, Rb, and Cl. Due
to the biological importance of Na and K, these two ions were
studied in the greatest detail.
The results of this research showed that, at UO₂⁺⁺ concentrations...
The objectives of this study were to evaluate environmental
factors influencing use of several plant communities by cattle, elk
and deer; determine under story production by plant species and the
amount utilized by cattle, elk and deer in certain plant communities;
evaluate the interactions of range use between cattle, elk...
The objectives of this study were to: 1) determine production
of plant species and utilization by cattle, sheep and deer as related
to plant communities and timber management practices and 2) evaluate
the interaction of range use between cattle and deer and between sheep
and deer as affected by site...