Thesis (M.A.)--University of Alberta, 1952. / Includes bibliographical references (leaves 167-170). Also available online as part of: Our roots/Nos Racines.

Thesis (M.A.)--University of Montana, 2007. / Description based on contents viewed July 27, 2007; title from title screen. Includes bibliographical references (p. 88-90).

No description available.

Over the past two decades, the mountain pine beetle (MPB) has killed millions of acres of forest across western North America. In addition to extensive environmental disturbance, the MPB epidemic has deeply impacted human systems, including motivating the formation of novel environmental governance arrangements. In Colorado, the Colorado Bark Beetle Cooperative (CBBC) formed as a collaboration between federal, state, and local stakeholders to address the epidemic. This study used a combination of GIS analysis and qualitative document analysis to understand how the CBBC has been able to respond adaptively to changes in the landscape pattern of MPB damage. I found that the CBBC was able to respond adaptively to changes in the MPB outbreak through shifting their organizational direction and activities. However, the adaptive capacity of the group was constrained by logistical factors, the declining importance of MPB at a national level, and the ways in which the group framed the MPB problem.

No description available.

The vegetation of the high mountain grasslands of the north-eastern Transvaal was sampled by using stratification based on geology and land types. Data was classified by TWINSPAN procedures and refined by using the Braun··Bianquet method. This resulted in the recognition of three vegetation units namely wetlands, boulderies and grasslands which represent a moisture gradient. Wetlands comprised four major communities and ten minor plant communities while boulderies resulted in four major communities and seven minor communities. The grasslands comprised four major plant communities which were subdivided into twenty eight minor communities. All identified communities were described and ecologically interpreted and a species list was compiled combining the data gathered in the area by other authors. / Dissertation (MSc)--University of Pretoria, 2013. / Plant Science / unrestricted

Quantitative and qualitative vegetation and environmental data from one-hundred-fourteen sample plots were used to characterize and evaluate ecological relationships and dynamics previously little known for the Subalpine Mountain Hemlock Zone on the southwestern British Columbia mainland. Environmental analyses, presented in detail, include the description of thirty-six kinds of soil representing several major categories. From the analytical data, each sample plot consists of a single set of values representing local historically developed variations and patterns of vegetation, soil, microclimate and topography within the biogeoclimatic zonal concept of Krajina (1962). A combined vegetation-environment synthesis resulted in the characterization of ecosystematic units at several levels of generalization (zone, subzone, order, alliance, association, subassociation and variant) within the following classification scheme: (A) Parkland Subzone i) Chionophilous (Schneetalchen) units, with snow -duration of at least 9 months 1) Vegetation of unstable sheet-wash slopes or hamada-like surfaces 2) Sedge vegetation of semi-terrestrial basin habitats ii) Moderately chionophilous units with snow duration averaging between 8 and 9 months 1) Herbaceous vegetation of stream-edge, spring-line or semi-terrestrial habitats 2) Heath-like or low shrub vegetation of terrestrial mesic to hygric habitats iii) Chionophobous forested units with snow duration averaging about 8 months or less 1) Mesic habitats 2) Moderately dry habitats (B) Forest Subzone i) Forested units lacking a seepage influence or with only a temporary seepage influence 1) Moderately dry lithic habitats or habitats with shallow soils 2) Mesic habitats with shallow to deep soils 3) Hygric habitats with deep soils and a temporary seepage influence ii) Forested units of hygric habitats with a permanent seepage influence 1) Seepage fast-flowing in stream-edge or spring-line habitats 2) Seepage slow-moving or stagnating in depressions or spring-line habitats iii) Non-forested semi-terrestrial moor habitats As orders and alliances include units of lower rank with strong environmental and floristic similarities to those found in other biogeoclimatic zones and subzones and elsewhere, a new dimension is added to the organization of ecosystematic units. The Subalpine Mountain Hemlock Zone coincides with the main distributional area of Tsuga mertensiana -- an area with a cool, snowy forest climate (Dfc after Koppen), podzolization and gleization as the dominant soil-forming processes, and with the development of Humic and Humus Podzol soils with thick, acid accumulations of mycelial ecto-humus on mesic zonal habitats. Discontinuity in the forest cover coinciding with an increasing duration of snow provides a physiognomic, floristic and climatic basis for the recognition of the Parkland and Forest Subzones. Vegetation and soil patterns and relationships in the Parkland Subzone are evidently most influenced by snow duration, soil moisture regime, topography and microclimate, whereas soil moisture regime, land type and topography are important influences in the Forest Subzone. The interplay of compensatory influences may promote the development of similar floristic patterns on different topographic forms on an intra- and interzonal scale. The environmentally integrating influence of snow depth and duration in the Parkland Subzone results in sharp floristic and microclimatic patterns. Vegetation may have a strong autogenic influence on microenvironmental dynamics by hastening snow melt and extending length of the growing season over short distances. Dynamics within the zone favoring successional trends are proceeding at a very slow rate. Climatic changes shortening the duration of snow rather than cumulative autogenic influences would probably contribute most to vegetation changes at high elevations in the subalpine zone. / Science, Faculty of / Botany, Department of / Graduate

Volatile constituents of bark from the two species of pine hosts of the mountain pine beetle, (Dendroctonus ponderosae Hopkins) were investigated as postulated factors in host tree discovery and selective attack by the insect. The anemo-olfactory, klinokinetic and klinotactic responses of pedestrian adult flown females to odors of different aged pines of the species Pinus ponderosa Laws, (ponderosa pine) and Pinus monticola Dougl. (western white pine) were used as criteria to test for evidence as to possible involvement of host tree volatiles in host selection. Volatile substances from pine bark were collected through sublimation under vacuum from frozen state. The volatile extracts were analyzed by Gas-Liquid Chromatography. Total volatile extracts and their ether soluble fraction from mature pine trees were "attractive" to beetles, whereas those from saplings were "repellent." No qualitative differences were found in the ether-soluble fraction of mature trees and saplings respectively, but proportions of individual constituents in the extracts differed. Ethanol at various concentrations caused arrestance of the anemo-olfactory response of pedestrian beetles. As a constituent of trees under stress ethanol may thus play an important role in the programme of responses which lead ultimately to attack. Problems encountered during the storage of tree samples and their extracts have been discussed. / Forestry, Faculty of / Graduate

This thesis attempts to devise a classification of ecosystematic units which reflect the rates, patterns and environmental determinants of plant community formation on recently deglaciated terrain. A series of three glacial valleys located in Garibaldi Park, approximately 60 miles east of Vancouver, British Columbia, and lying between elevations of 4800 and 5000 feet above sea level, were studied. The valleys lie in a transition area between coastal and interior biogeoclimatic zones and thus derive their pioneer flora from elements of the Coastal Subalpine Mountain Hemlock Zone, the Coastal Alpine Zone and the Interior Engelmann Spruce - Subalpine Fir Zone. Climate, geology and soil development in the three valleys were studied in order to provide an understanding of the macroenvironmental conditions under which the vegetations was developing. Temperature, humidity, and rainfall were measured for three field seasons (1965 through 1967) to determine the degree of climatic homogeneity of the study area, to examine the effect of glacial proximity on microclimate within the valleys and to establish a gross moisture balance for the growing season. Snow duration was noted for all vegetated sites. A brief description of the parent rocks contributing to the glacial till in the valleys is provided. The chronology of ice retreat in each valley is documented by growth ring analysis of trees established on differently aged surfaces and by reference to studies of synchronous glacial movements in western North America. Soil development was studied by chemical analysis of soil samples taken from pits associated with various plant communities. Changes in total nitrogen, organic matter, C:N ratio, cation exchange capacity and macronutrient cations have been noted with advancing substrate age and altered vegetation cover. Vegetation was sampled using 16 m² sample plots in which vegetation stratification, floristic composition and species abundance-dominance, sociability and vigour were estimated. A classification of ecosystematic units was then synthesized by grouping samples on the basis of overall floristic similarity, dominance by a characteristic combination of species and uniformity of ecotope. The phytosociological synthesis was compared with a cluster analysis of the sample plots using species presence and cover, a method which yielded a similar but not identical set of groups to the ecosystem units. A total of twelve ecosystem units was delimited representing a number of pathways in plant succession and ranging in age from 40 - 150 years since ice retreat. Detailed ecological relationships with the ecosystematic units have been determined from microenvironmental measurements, soil nutrient analyses, sap pressure studies, and autecological analyses associated with the original sample plots. Variations in soil moisture content, surface temperature extremes and snow duration were recorded and correlated with plant community development. Soil nutrient availability was determined for soil samples from pits within sample plots representing the various ecosystematic units. Apparatus and field methods were developed to monitor the diurnal variation of internal moisture stress for a number of successionally important species. Sap pressure, negative tension on the water stream in the xylem, was correlated with net radiation to the plants and atmospheric moisture deficits. A statistical comparison of sap pressure regimes and distribution of four Salix shows that their distribution into different ecosystem types is predictable from their mean sap pressures. For all species of significant coverage an autecological summary has been prepared from plot analysis records showing their modalities to hygrotope, snow duration and age of substrate since ice retreat. Climate, geology, substrate chronology, soil development, microenvironment, autecological relationships, and phytosociological units with their successional roles have been combined to provide a synecological summary for each ecosystematic unit. Maps of the glacial valleys are presented which show the actual distribution of individual communities within each unit. / Science, Faculty of / Botany, Department of / Graduate

. High grade metamorphic rocks belonging to the Shuswap Complex crop out in the southern Okanagan region of British Columbia. An area of these rocks previously mapped by Bostock (1940) as the Vaseaux Formation was studied. A local structural lithologic succession is postulated comprising. of four units, whose present thicknesses are variable but do not generally exceed 100 ft. Four phases of penetrative deformation are recognized. The first, recumbent isoclinal with northerly trends, was succeeded by a second recumbent isoclinal phase, with northwesterly trends. Phase 3 produced easterly trending upright close folds, and later open upright northwesterly and northerly trending folds characterize phase 4. Five intrusive events punctuate the structural history. Two precede phase 2 and three postdate it. Rb-Sr isotopic dating of these intrusions provides a Tertiary age for phase 4, and a pre-mid-Jurassic age for phase 2. The existence of a mid-Jurassic metamorphism can also be inferred from the isotopic data. Based on interpretations of data from adjacent areas it appears that phases 1, 2 and 3, and related events are all facets of the Lower Mississippian Caribooan Orogeny. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate