Thesis (Ph.D.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2009/06/08). Includes bibliographical references.

The ectomycorrhizal communities of three aspen-covered sites in southwestern Montana and southeastern Idaho with varying stand age, conditions, and soil types were compared. In all, 39 species of ectomycorrhizal fungi were associated with P. tremuloides. Dominant fungal species varied by site. Species reported on acidic soils in Europe and other species reported to be "early colonizers" were found exclusively on the acidic soils of the Butte site. Many "late stage" fungi such as Amanitas and Cortinarii were found on the older and more productive sites. Nine isolates of ectomycorrhizal fungi were tested for their ability to form mycorrhizae with P. tremuloides. Amanita muscaria v. formosa, A. pantherina, Paxillus vernalis, and Pisolithus tinctorius formed mantles and Hartig nets. Inocybe lacera and Piloderma croceum formed mantles but no Hartig nets. Dry weight, stem diameter, height and number of roottips increased in the young aspen seedlings inoculated with a majority of the fungi listed above. The implications for aspen survival and growth are discussed. / Master of Science

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Plant-herbivore interactions play a significant role in the structure and functioning of ecosystems. Co-evolutionary theory suggests that plant defenses evolved due to herbivores and herbivore pressure can shape the genetic composition of their food resources. We used interactions between North American porcupines (Erethizon dorsatum) and trembling aspens ( Populus tremuloides) as a system to investigate this theory's important assumption that herbivores select food sources based on genetically controlled traits. We confirmed that porcupines exhibit intra-specific food selection and that this is linked to the genetic composition of the aspens. We also demonstrated that variation in phenolic glycosides and condensed tannins are strong components of this selection, thereby creating an important link between genetics, plant chemistry, and mammalian herbivory. We investigated potential impacts of porcupine herbivory on aspen using fluctuating asymmetry, however we did not detect any stress on heavily eaten trees, thereby questioning the validity of this tool for this study system.

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Thesis (Ph. D.)--Institute of Paper Chemistry, 1969. / Includes bibliographical references (p. 54-57).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1959. / Includes bibliographical references (p. 88-119).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1975. / Includes bibliographical references (p. 97-100).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1975. / Includes bibliographical references (p. 60-67).

No description available.