Thesis (Ph. D.)--Oregon State University, 1974. / Typescript (photocopy). Maps folded in pocket. Includes bibliographical references. Also available via the World Wide Web.

The vegetative communities in the subalpine meadows of Hunts Cove, Mt. Jefferson, and some of the major environmental factors affecting them were studied in the summer of 1971. Hunts Cove is in the subalpine Tsuga mertensiana parkland of the Central Oregon High Cascades. Habitats within the Cove vary considerably; elevation changes from 1500 m to 1900 m; water regime ranges from bogs and seeps to desert; snowlie varies as much as two months at different points in the same year. Estimates of vegetative cover and frequency were taken on 300 quadrats. Snow lie was monitored on a weekly basis. Soils were collected and analyzed. Eleven meadow communities were distinguished. They are: A. The short sedge communities, 1) Carex nigricans-Aster and 2) Carex nigricans-Polytrichum on late snowfree, poorly drained sites; B. Bryophyte, on very late snowfree, damp, shaded soil; C. Heath communities on well drained sites, 1) Phyllodoce-Cassiope on exposed late snowfree slopes, 2) Vaccinium deliciosum on moderately late snowfree slopes and 3) Potentilla-Carex nigricans on very late snowfree sites with rodent activity; D. Senecio lush herb on mesic warm sites; E. Hydric communities, 1) Eleocharis-Aulacomnium occurring in stagnant water, 2) Carex rostrata-Sphagnum in freely moving water, 3) Carex scopulorum in seeps and bogs with permanent water supply, probably an edaphic climax, and 4) Carex sitchensis in swamps flooded during meltoff. These communities were arrayed in a floristic ordination and the position of all hydric, lush herb, and short sedge sample plots was found to parallel snowfree dates. Well drained heath communities became snowfree in the order expected from other studies. Comparison of the communities with other studies from the Northwest suggests Phyllodoce-Cassiope, Vaccinium deliciosum and the Carex nigricans communities to be parts of a consistent vegetative pattern extending north into Southern B. C. / Graduation date: 1973

Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2009/06/23). Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 125-136). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 190-196). Also available on the World Wide Web.

Thesis (M. Sc.)--University of Alberta, 1990. / Submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Science, Department of Botany. Includes bibliographical references. Available also in electronic format on the Internet.

This thesis offers the first detailed palaeoenvironmental analysis of wetland areas within sub-Arctic enclosed homefield’s. Significance of meadows were previously mentioned only briefly in the literature, suggesting influences in settlement site selection as well as importance in quality fodder production, producing up to two thirds of total hay resources in a somewhat marginal agricultural landscape. Given the importance of hay resources in Iceland it seems unusual these areas have received so little attention to date, despite extensive research on all other aspects of the Norse farm system. The organic sediments within the meadows, given their development in-situ over extended time periods, have the ability to record aspects of the intimate relationship between societal and environmental change, and so in a robust and holistic way our methods set integrates radiocarbon measurement, tephrochronology, palynology and thin section micromorphology from the same core; reflecting these findings against existing paleoclimate and archaeological site data. This combined application of the core techniques – palynology and soil micromorphology, has proven successful in creating effective human ecodynamic records from each of the study farms. Records obtained from the three farm sites in northwest and northern Iceland exposed the varying importance and differing utilisation of these wetland areas. Meadows would appear to have played an import role in choice of settlement site across northern Iceland, through the provision of open areas, and additional and immediately available fodder resources at settlement, in a landscape dominated by dense scrub. Meadows were found to have been in continuous use, albeit at varying levels of intensity, from settlement to the present day. In this respect the semi-natural resources are found to be remarkably resilient, demonstrating little alterations to their composition following severe climatic downturns, including that of the Little Ice Age, and volcanic eruption. Acting as a robust resource and safety buffer for settlements, contributing to fodder resources where reliability of other resources is jeopardised by environmental conditions. Research in the more marginal northwest peninsula provides the first evidence of artificially created wet meadows in Iceland, developed to give sustained fodder production for over-wintering livestock in an environment that inherently had a short growing season and lacked soil fertility. A further example of the nuanced land management practices adopted in the agriculturally fragile farmscapes of the Norse North Atlantic. The findings of the thesis have wider implications for understanding the emergence of resilient and sustainable communities in agriculturally marginal environments; to this end there remains many opportunities to use palaeoenvironmental research to study ecosystem responses to natural and anthropogenic stresses, giving us a better understanding of capacities to withstand future stresses.

This research aimed to determine whether wood microsites ("nurse logs"), which are regeneration sites in Pacific Northwest (PNW) subalpine forests, supported regeneration at timberline-alpine meadow borders. Upward advance of forests and conifer invasion into alpine meadows, which may be occurring in conjunction with climate warming, have gained worldwide attention. Successful alpine meadow seedling regeneration depends on suitable substrate availability, or microsites, for seedling establishment. To better understand factors associated with wood microsite occurrence, mechanisms of wood input were determined and four specific hypotheses were posed to assess: (1) seedling density and seedling survival; (2) growing season length, summer mean growing temperature, and growing degree hours (GDH); (3) active measures of seedling growth; and (4) global wood microsite climate associations. Of four studies, three were conducted in the Cascade Mountains of Washington state along a west - east precipitation gradient and one study, assessed various microsites globally. For Cascades-related research, wood and adjacent soil substrate temperature, moisture, and associated seedling density, survival, stomatal conductance, water potential, and leaf nitrogen were compared by percent transmitted radiation at 4 to 14 study sites. Analysis of variance (ANOVA), t-tests, regressions, and classification and regression trees (CARTs) were used to assess significance of comparisons. Wood microsites, common at 13 of 14 random Cascade sites, had greater seedling densities, greater seedling survival, greater volumetric moisture content (VWC), greater temperature, and greater number of GDH, as compared to adjacent soils. Greater seedling densities were positively associated with VWC (> 12%), conditions most commonly associated with wood substrate presence. For sites having > 25% percent transmitted radiation, positive relationships existed between stomatal conductance and VWC. Globally, high-elevation forests with wood microsites had mean annual precipitation from 86 cm to 320 cm and mean annual temperatures from 1.5°C to 4.7°C. In general, wood microsites facilitated alpine meadow regeneration better than adjacent soils. Management implications included enhanced understanding of factors associated with upward forest advance and wood use for restoration. Globally, wood microsites importance is likely underrepresented. Wood microsites role with warming climate will depend on precipitation pattern, timing, magnitude, and frequency.