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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Ecology of understory and below-ground communities in lodgepole pine forests under changing disturbance regimes

McIntosh, Anne C. S. Unknown Date
No description available.
52

Impact of Mountain Pine Beetle Attack on Water Balance of Lodgepole Pine Forests in Alberta

Pina Poujol, Pablo Cesar Unknown Date
No description available.
53

Variation in reproductive characteristics of lodgepole pine (Pinus contorta var. latifolia) in British Columbia

Berland, Anne 09 January 2014 (has links)
Lodgepole pine (Pinus contorta var. latifolia) is the most wide-ranging pine in North America. Populations in British Columbia vary widely in phenotypic and genotypic characteristics. The effect of climate on variation in reproductive characteristics has never been examined, yet is vital to the production of seed necessary for reforestation. This study aims to determine the relationship between the climate in B.C and variation in female cone and seed characteristics. The study makes use of the Illingworth provenance trial, sixty common garden plots that are distributed throughout British Columbia. Female cones from six provenances were collected at 21 sites during the summer of 2012. The number of scales was counted and maximum length was measured for each cone. Seed was extracted and counted. Variables were pooled for each tree. The climate at each site was described using data from ClimateWNA. Principal components analysis was used to reduce the highly correlated data set to the first two principal components (PC1 and PC2), which together described 76.7% of the variation in the data. PC1 was most closely aligned with variables related to temperature, the number of frost-free days, and degree-days above 5°C or below 0°C. PC2 was most closely aligned with precipitation and moisture variables. The reproductive variables were moderately positively correlated with one another. Analysis of variance indicated that average cone length and the average number of seeds per cone were significantly affected by both site and provenance, however the average number of seeds per cone was not. Average values of each reproductive trait for each site were modelled against the first two principal components using multiple analysis of variance and univariate linear modelling. The best-fit model for the average number of scales per cone included PC1 and PC2, however the model only described 4.9% of the variation in the data. The best-fit model for the number of seeds included only PC1, and iv the model only explained 4.1% of the variation in the data. The model for average cone length had the strongest results, with a model that included PC2 and explained 18.7% of the data. The results of the study indicate that climate is not the most important factor in predicting reproductive characteristics such as cone length, and the number of scales and seed per cone. The significant effect of moisture on average cone length was the strongest relationship identified in the study. The reproductive traits were best described by their stability across the climates of the test sites. High genetic variation in lodgepole pine populations may be contributing to the stability of reproductive traits. Lodgepole pine female cone and seed traits were stable for mature trees over a wide range of provenances and climate regions. / Graduate / 0309 / 0478 / anne.berland@gmail.com
54

Development of Bio-based Phenol Formaldehyde Resol Resins Using Mountain Pine Beetle Infested Lodgepole Pine Barks

Zhao, Yong 13 August 2013 (has links)
Phenol formaldehyde (PF) resol resins have long been used widely as wood adhesives due to their excellent bonding performance, water resistance and durability. With the growing concern for fossil fuel depletion and climate change, there is a strong interest in exploring renewable biomass materials as substitutes for petroleum-based feedstock. Bark, rich in phenolic compounds, has demonstrated potential to partially substitute phenol in synthesizing bio-based PF resins. In this study, acid-catalyzed phenol liquefaction and alkaline extraction were used to convert mountain pine beetle (MPB; Dendroctonus ponderosae) infested lodgepole pine (Pinus contorta) barks to phenol substitutes, liquefied bark and bark extractives. Two types of bio-based phenol formaldehyde (PF) resol resins, namely liquefied bark-PF resin and bark extractive-PF resins, were then synthesized and characterized. It was found that acid-catalyzed phenol liquefaction and alkaline extraction were effective conversion methods to obtain phenol substitute with the maximum yield of 85% and 68%, respectively. The bio-based PF resol resins had higher molecular weights, higher polydispersity indices, shorter gel times, and faster curing rates than the lab synthesized control PF resin without the bark components. Based on the lap-shear tests, the bio-based PF resol resins exhibited comparable wet and dry bonding strength to lab PF resin and commercial PF resin. The post-curing thermal stability of the bio-based PF resins was similar to the lab control PF resin. The liquid-state 13C nuclear magnetic resonance (NMR) study revealed significant influences on the resin structures by the inclusion of the bark components. Methylene ether bridges, which were absent in the lab PF resin, were found in the bio-based PF resins. The bark components favored the formation of para-ortho methylene linkages in the bio-based bark extractive-PF resins. The liquefied bark-PF resin showed a higher ratio of para-para/ortho-para methylene link (-CH2-), a higher unsubstituted/substituted hydrogen (-H/-CH2OH) ratio and a higher methylol/methylene (-CH2OH/-CH2-) ratio than the bark extractive-PF resin. Both tannin components of bark alkaline extractives and phenolated barks contributed to the acceleration of the curing rate of the bio-based resins. This research demonstrated the promise of the bio-based PF resins containing either bark alkaline extractives or liquefied barks as environmentally friendly alternatives to PF adhesives derived solely from fossil fuel based phenol and proposed a novel higher value-added application of the largely available barks from the mountain pine beetle-infested lodgepole pine trees.
55

Development of Bio-based Phenol Formaldehyde Resol Resins Using Mountain Pine Beetle Infested Lodgepole Pine Barks

Zhao, Yong 13 August 2013 (has links)
Phenol formaldehyde (PF) resol resins have long been used widely as wood adhesives due to their excellent bonding performance, water resistance and durability. With the growing concern for fossil fuel depletion and climate change, there is a strong interest in exploring renewable biomass materials as substitutes for petroleum-based feedstock. Bark, rich in phenolic compounds, has demonstrated potential to partially substitute phenol in synthesizing bio-based PF resins. In this study, acid-catalyzed phenol liquefaction and alkaline extraction were used to convert mountain pine beetle (MPB; Dendroctonus ponderosae) infested lodgepole pine (Pinus contorta) barks to phenol substitutes, liquefied bark and bark extractives. Two types of bio-based phenol formaldehyde (PF) resol resins, namely liquefied bark-PF resin and bark extractive-PF resins, were then synthesized and characterized. It was found that acid-catalyzed phenol liquefaction and alkaline extraction were effective conversion methods to obtain phenol substitute with the maximum yield of 85% and 68%, respectively. The bio-based PF resol resins had higher molecular weights, higher polydispersity indices, shorter gel times, and faster curing rates than the lab synthesized control PF resin without the bark components. Based on the lap-shear tests, the bio-based PF resol resins exhibited comparable wet and dry bonding strength to lab PF resin and commercial PF resin. The post-curing thermal stability of the bio-based PF resins was similar to the lab control PF resin. The liquid-state 13C nuclear magnetic resonance (NMR) study revealed significant influences on the resin structures by the inclusion of the bark components. Methylene ether bridges, which were absent in the lab PF resin, were found in the bio-based PF resins. The bark components favored the formation of para-ortho methylene linkages in the bio-based bark extractive-PF resins. The liquefied bark-PF resin showed a higher ratio of para-para/ortho-para methylene link (-CH2-), a higher unsubstituted/substituted hydrogen (-H/-CH2OH) ratio and a higher methylol/methylene (-CH2OH/-CH2-) ratio than the bark extractive-PF resin. Both tannin components of bark alkaline extractives and phenolated barks contributed to the acceleration of the curing rate of the bio-based resins. This research demonstrated the promise of the bio-based PF resins containing either bark alkaline extractives or liquefied barks as environmentally friendly alternatives to PF adhesives derived solely from fossil fuel based phenol and proposed a novel higher value-added application of the largely available barks from the mountain pine beetle-infested lodgepole pine trees.
56

Evaluation of coniferous forest management practices on carbon pools, soil biogeochemical processes, and economic profitability

Chatterjee, Amitava. January 2007 (has links)
Thesis (Ph.D.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 16, 2009). Includes bibliographical references (p. 81-84).
57

Interactions of white pine blister rust, host species, and mountain pine beetle in whitebark pine ecosystems in the Greater Yellowstone

Bockino, Nancy Karin. January 2008 (has links)
Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on June 26, 2009). Includes bibliographical references (p. 86-111).
58

The vegetation dynamics of pinus contorta forest, Crater Lake National Park, Oregon /

Zeigler, Robert S. January 1978 (has links)
Thesis (M.S.)-Oregon State University, 1978. / Includes bibliographical referenes (leaves 151-162). Also available via the Internet.
59

Effects of root growth and physiology on drought resistance in Douglas-fir, lodgepole pine, and white spruce seedlings

Smit, Julie 10 July 2018 (has links)
Two aspects of drought resistance were investigated on wet and dry ecotypes of three conifer species: 1) the relative importance of drought avoidance and drought tolerance mechanisms in resisting drought stress was assessed on Douglas-fir (Pseudotsuga menzieseii) and lodgepole pine (Pinus contorta) seedlings, and 2) the effects of drought on root hydraulic conductance and low temperature, on root water flow rates Were assessed on first-year seedlings of Douglas-fir, lodgepole pine and white spruce (Picea glauca). To study drought avoidance, Douglas-fir and lodgepole pine seedlings were grown in sealed containers in wet (522% water content) or dry (318% water content) peat/vermiculite soil in a factorial treatment design. Dry weights, water use, and root length were determined for seedlings at each of five harvests and stomatal conductance and shoot water potentials were measured during the last 12 weeks of the experiment. Lodgepole pine seedlings had greater dry matter production, water use, stomatal conductance and new root length than Douglas-fir seedlings. New root weight of lodgepole pine seedlings exceeded that of Douglas-fir seedlings during the last five weeks of the experiment, and specific root length of new roots was higher for lodgepole pine seedlings throughout the experiment. Douglas-fir seedlings showed higher water use efficiency (WUE) than lodgepole pine seedlings, although water uptake rates per unit of root dry weight showed little difference between species. Soil water treatment influenced specific root length of new roots, water uptake per unit of new root length, and WUE in Douglas-fir seedlings more than in lodgepole pine seedlings. To study drought tolerance, Douglas-fir and lodgepole pine seedlings were grown under drought and well-watered conditions. At each of three harvests a pressure-volume curve was produced for each seedling. Douglas-fir maintained a lower osmotic potential at full saturation [special characters omitted] and lower turgor loss point [special characters omitted] than lodgepole pine under both watering regimes,. Both species had lower [special characters omitted] when drought-stressed. Douglas-fir appears to be a more conservative species, maintaining low stomatal conductance and tolerating drought conditions, whereas lodgepole pine avoids drought by producing large amounts of roots to exploit the soil resource. To study root hydraulic conductance (Lproot) and water flow rates through roots (WFRR), water flow was measured through de-topped roots of Douglas-fir, lodgepole pine, and white spruce seedlings in a pressure chamber. In a drought experiment, seedlings were grown in sandy soil in a greenhouse under drought and well-watered conditions during their first growing season and, in a low temperature experiment, seedlings were grown in sandy soil in growth chambers at 25/20°C (day/night) and 15/10°C, In the drought experiment, water flow through roots was measured at three pressures. No differences in Lproot were found for Douglas-fir and white spruce seedlings grown under the two watering regimes, however, lodgepole pine seedlings had reduced Lproot when grown under drought conditions. Welk watered seedlings of lodgepole pine and white spruce had higher Lpr00t in 1989 than in 1990 whereas Douglas-fir seedlings had the same Lproot in both years. In the low temperature experiment, WFRR was measured at 1.0 MPa and temperatures of 20°C for 24 hours or 20°, 12°, and 4°C for 18, 15, and 15 hours respectively. At 20°C, white spruce seedlings had higher WFRR than the other two species. Lodgepole pine and white spruce seedlings grown in the 1S°/10°C growth chamber had higher WFRR than seedlings grown in the 25°/20°C growth chamber. Water flow rate decreased with temperature in all three species. After correcting for viscosity, all seedlings had lower WFRR with reduced temperature, except for Douglas-fir and white spruce seedlings grown at 15°/10°C which had the same WFRR at 20°C and 12°C. Therefore, Douglas-fir and white spruce seedlings were found to become less sensitive to low temperature (chilling) stress when pre-conditioned at low temperatures. In the drought and low temperature studies, dry weight biomass of white spruce was lowest but white spruce had a greater specific root length than lodgepole pine and Douglas-fir. In the drought study, biomass production in seedlings from wet ecotypes of each species was more reduced when drought-stressed than seedlings from dry ecotypes. / Graduate
60

Relative susceptibility of interior spruce (Picea glauca x engelmannii engelm.) and lodgepole pine (Pinus contorta Dougl. var. latifolia engelm.) to Inonotus tomentosus (Fr.) Teng in central British Columbia

Schulting, Peter John January 1987 (has links)
Twenty sample plots located in Inonotus tomentosus (Fr.) Teng centers in mixed lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and interior spruce (Picea glauca x engelmannii Engelm.) stands in central British Columbia were studied to investigate the behaviour of, and variation in host species attacked by the pathogen. The effect of infection on the radial increment of spruce and pine was studied by measuring increment bores. Characteristics of the fungus in culture were studied using isolates obtained from each of the study plots. In some cases, the fungus was found to behave differently on spruce and pine. In pine, advanced necrosis of the cambium and phloem of the roots caused crown thinning and eventual standing mortality. In spruce, decay of the heartwood and inner xylem of the roots caused windfall of the tree, often before expression of noticeable crown symptoms. In both host species studied, spread was commonly observed from infected to healthy, contacting roots. Possible cases of spore inoculation through root wounds were also found. In all plots, pine showed a higher infection level than spruce. Subalpine fir (Abies lasiocarpa (Hook.) Nutt.) and Douglas-fir (Pseudotsuqa menziesii (Mirb.) Franco) present within the plots were not found to be infected. Infection by I. tomentosus was not found to reduce significantly the basal area increment in pine or spruce. The fungus in culture demonstrated a large amount of variation in growth rate, mycelium color and mat color and texture. Such variation occurred both within and among isolates, and could not be related to the host species from which the isolate was obtained. / Forestry, Faculty of / Graduate

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