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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.
1

The Forest for the Trees: Gifford Pinchot’s Principles of Conservation

Murray, Leslie M. 01 August 2018 (has links)
Gifford Pinchot’s principles of conservation embody the democratic principles of the United States and how those principles remain relevant today. The three central characteristics of Pinchot’s principles of conservation are wise use, avoiding waste, and securing the autonomy of democratic citizens by preventing monopolistic control over our natural resources. Pinchot’s aim place democratic aspirations at the fore. A case study of the environmental degradation revealed throughout the life-cycle of the cellular phone exhibits how Pinchot’s principles are not only relevant, but sorely needed today. Furthermore, this case study also reveals how globalized corporatism has become the antithesis of the democratic aims of the global citizenry. Pinchot’s principles advise us to check the global monopolies of multinational corporations and greed for greed’s sake to secure a democratic future for the most people, in perpetuity. Though his principles are often neglected, they are more relevant now than ever.
2

Microbial community structure as influenced by season and stand age in a Douglas-fir (Pseudotsuga menziesii) ecosystem

Kucera, Jennifer Moore 01 June 2005 (has links)
Forest harvest can have significant impacts on forest ecosystems that may influence the capacity of soils to sequester carbon (C). The microbial community controls decomposition, which is a critical process in partitioning litter- and root-C between CO₂ and storage in semi-permanent soil-C pools. The objectives of this study were to determine the effect of clear-cutting and stand age on: 1) temporal dynamics of soil microbial community (SMC) structure and physiological status; and 2) shifts among microbial functional groups in taking up ¹³C-labeled plant materials during decomposition. The experiment was conducted in Douglas-fir ecosystems within the Gifford Pinchot National Forest, Washington. We chose stands of three different ages: old-growth where trees are between 300 and 500 years old; an 8-year old stand; and a 25-year old stand. Phospholipid fatty acid (PLFA) profiling and ¹³C-PLFA labeling techniques along with the ratio of saturated to monounsaturated PLFAs and the ratios of cyclopropyl PLFAs to their monoenoic precursors as microbial physiological stress markers were utilized. Microbial PLFA profiles showed that SMC structure and physiological status was most affected by season and secondarily by time since clear-cutting. Total microbial biomass and bacterial and fungal biomass were significantly reduced in CC8 but not in CC25 sites relative to old-growth sites. Total microbial biomass concentration was lowest and the stress indicators were highest in August, which corresponded to low soil moisture and high temperatures. The relative amount of ¹³C incorporated into PLFAs was also influenced by stand age and ¹³C source (¹³C-labeled litter vs. ¹³C-labeled root material). A significantly greater amount of ¹³C was incorporated in CC8 samples compared to OG1 samples in five out of the seven sample dates. Additionally, a significantly greater proportion of ¹³C was incorporated into soil samples containing the ¹³C-labeled litter material relative to samples containing ¹³C-labeled root material in four out of the seven dates. In general, 18:lω9 and 18:2ω6,9 (common fungal biomarkers) had the greatest amount of ¹³C incorporation throughout the study period in both clear-cut and old-growth sites, indicating the important role of fungi in the decomposition of litter and root material and translocation of C within soil layers. / Graduation date: 2006
3

The water and energy dynamics of an old-growth seasonal temperate rainforest

Link, Timothy E. 02 October 2001 (has links)
In the Pacific Northwest (PNW), concern about the impacts of climate and land cover change on water resources, flood-generating processes, and ecosystem dynamics emphasize the need for a mechanistic understanding of the interactions between forest canopies and hydrological processes. A detailed measurement and modeling program during the 1999 and 2000 hydrologic years characterized hydrological conditions and processes in a 500-600 year old Douglas fir-western hemlock seasonal temperate rainforest. The measurement program included sub-canopy arrays of radiometers, tipping bucket rain gauges, and soil temperature and moisture probes, to supplement a vertical temperature and humidity profile within the forest canopy. Analysis of the precipitation interception characteristics of the canopy indicated that the mean direct throughfall proportion was 0.36, and the mean saturation storage was 3.3 mm. Evaporation from small storms insufficient to saturate the canopy comprised 19% of the net interception loss, and canopy drying and evaporation during rainfall accounted for 47% and 33% of the net loss, respectively. Results of the measurement program were used to modify the Simultaneous Heat and Water (SHAW) model for forested systems. Changes to the model include improved representation of interception dynamics, stomatal conductance, and within-canopy energy transfer processes. The model effectively simulated canopy air and vapor density profiles, snowcover processes, throughfall, soil water content profiles, shallow soil temperatures, and transpiration fluxes for both a calibration period and for an uncalibrated year. Soil warming at bare locations was delayed until most of the snowcover ablated due to the large heat sink associated with the residual snow patches. During the summer, simulated evapotranspiration decreased from a maximum monthly mean of 2.17 mm day����� in July to 1.34 mm day����� in September, as a result of declining soil moisture and net radiation. Our results indicate that a relatively simple parameterization of the SHAW model for the vegetation canopy can accurately simulate seasonal hydrologic fluxes in this environment. Application and validation of the model in other forest systems will establish similarities and differences in the interactions of vegetation and hydrology, and assess the sensitivity of other systems to natural and anthropogenic perturbations. / Graduation date: 2002
4

Contested Visions of Place: People, Power, and Perception on the Columbia's North Shore, 1805-1913

Sinclair, Donna Lynn 11 February 2004 (has links)
This is a narrative of place, of intersections between people, power, and perception of landscape. The environs of the Columbia River Gorge create a very distinct sense of place. Where once a series of three rapids - the Cascades of the Columbia - blocked industrial upriver transport, now Bonneville Dam and Locks allows smooth passage. To the north the vast 1.3 million acre Gifford Pinchot National Forest dominates the landscape. On the Columbia's banks lies the town of Stevenson, Washington, with Carson a few miles away, in a transitory ecological zone between east and west, at the forest's edge. There, community development has been manifestly influenced by human relationships to the landscape. Contested visions of place during the nineteenth century resulted in violent conflict and framed debates over place.Examining struggles over who would control access, first to the Cascades of the Columbia, and then to the timber of the Wind River Valley, provides a venue for examining power - of nature, ideas, and changing human cultures as overlapping groups imposed their views of the good life onto the landscape. As each successive group gained power, the relationships of humans to the land, and to one another, changed. By examining historic connections between river and forest, and between human communities to each, this study identifies multiple meanings of the same environment for different groups. I use a bioregional approach, exploring relationships between land, people and resources on the Columbia's north bank between 1805 and 1913. Power relations at the Cascades and in the forest were determined through conflict, negotiation, and the federal government, with the human relationship to nature influencing outcomes. Conflict often resulted from struggles over access to place, while human groups negotiated their place within the landscape. Nature privileged one group over another through disease, fire, and human perception, while the United States government co-opted place through public land laws, Indian removal, and by measuring and bounding the landscape. Who gained access to the river and forest of the Columbia's north shore, and how they did it, is the focus of this story.

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