Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.A.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 83-84.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Thesis (M.S.)--Oregon State University, 1972. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

No description available.

Successful establishment of boreal tree seedlings like trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca (Moench) Voss.) in reclaimed oil sands mining sites is often limited by low nutrient availability and competition from the ground cover vegetation like planted cover crops and weeds. Competing vegetation can adversely affect seedling establishment by augmenting the impacts of moisture and nutrient stress. Despite high potential of barley (Hordeum vulgare L.) and oats (Avena sativa) as cover crops in oil sands reclamation, it was not well known how these crops interact with fertilization to influence early survival and growth of tree seedlings. This study evaluated the potential of fertilization and other silvicultural practices to improve revegetation success in oil sands sites reclaimed with peat-mineral mixture. Fertilizer application significantly increased height and root collar diameter (RCD) of tree seedlings in controlled environment greenhouse conditions, but not at a field research site near Fort McMurray, Alberta. In a greenhouse study, alleviating soil moisture stress significantly increased height, RCD, and biomass of tree seedlings. Vigorous growth of ground cover vegetation stimulated by fertilizer addition in both the greenhouse and field, largely controlled survival and growth responses of tree seedlings. Survival rates of tree seedlings were significantly decreased with increased fertilizer application rates, and no positive growth responses were observed in the field. Maximum seedlings survival (92%) was recorded without fertilization. Trembling aspen was sensitive to ground cover competition, whereas white spruce was unaffected. The inherent fertility of the peat-mineral mixture appeared sufficient for establishment and early growth of planted tree seedlings in recently reclaimed oil sands sites. Fertilization appeared to increase competition between tree seedlings and cover vegetation by promoting increased growth and competition for other resources like water. Effects on growth over the longer term (several years) should be evaluated in future studies.

Brush encroachment is a serious problem on pastures in Western Canada. It results in a loss of productivity and habitat for wildlife. Sixty-seven pastures were visited in Manitoba, Saskatchewan and Alberta. Approximately half were privately owned lands and the remainder were public lands. Each field sampled was divided into grass, shrub and forest strata, within each stratum vegetation cover was noted and biomass and soil samples were taken. A historical reconstruction was created using aerial photos dating back to the 1940s up until most recent photos available. Six cover classes were delineated and patch statistics were calculated. Information on historical management practices were obtained also. It was determined that woody encroachment is occurring on pastures, but no significant trends found between environmental factors and encroachment. Therefore it was concluded that management probably has the greatest impact on the occurrence and extent of woody encroachment.

In North America there has been an increasing appreciation for the value of trembling aspen (Populus tremuloides Michx.) as a source of timber. Moreover, trembling aspen stands and the understory vegetation that they support also provide valuable forage for livestock and wildlife. Timber harvesting and cattle grazing are often done on the same area of land in western Manitoba, though not simultaneously. The purpose of this project is to summarize the effects cattle grazing has on regeneration numbers and forest health in post-harvest aspen stands in the Aspen Parkland of western Manitoba.

Brush encroachment is a serious problem on pastures in Western Canada. It results in a loss of productivity and habitat for wildlife. Sixty-seven pastures were visited in Manitoba, Saskatchewan and Alberta. Approximately half were privately owned lands and the remainder were public lands. Each field sampled was divided into grass, shrub and forest strata, within each stratum vegetation cover was noted and biomass and soil samples were taken. A historical reconstruction was created using aerial photos dating back to the 1940s up until most recent photos available. Six cover classes were delineated and patch statistics were calculated. Information on historical management practices were obtained also. It was determined that woody encroachment is occurring on pastures, but no significant trends found between environmental factors and encroachment. Therefore it was concluded that management probably has the greatest impact on the occurrence and extent of woody encroachment.