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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

A Limnological Analysis of Ten Mountain Lakes

Burns, Gary Wayne 03 June 1993 (has links)
Ten mountain lakes were analyzed in order that they be assigned a trophic status. The lakes which are located in the Mount Hood National Forest of Oregon are Anvil, Beaver Pond, Cripple Creek, Fish, Gifford, Monon, Ollalie, Rimrock, Round, and Sportsman. The purpose of this report is to determine the productivity of these waters. Data were collected for analyses of temperature, dissolved oxygen concentration, Secchi depth, major ion concentration, light intensity versus depth, alkalinity, phytoplanktcn species composition/total density, and zooplankton species composition/total density. Samples were collected in Van Darn sampling bottles and returned to the laboratory for chemical analyses and taxonomic identification of biological organisms. Field profiles were taken for light intensity, temperature, dissolved oxygen concentration, specific conductivity, and depth using portable electronic equipment. A Secchi disk was used in the field for obtaining light extinction data. The lakes were assigned a trophic status according to carlson's Trophic State Index (Carlson, 1977). Beaver Pond Lake which is the most productive lake of the 10 surveyed had an average Secchi depth of 1.7 meters, an average soluble reactive phosphorous concentration of 59.8 ug/L, and an average chlorophyll-a concentration of 29.3 ug/L for the dates sampled. These values are consistent with lakes which are eutrophic. Ollalie Lake had an average Secchi depth of 13.2 meters, an average soluble reactive phosphorous concentration of 1.64 ug/L, and an average chlorophyll-a concentration of 0.28 ugfL. This lake is ultraoligotrophic-to-oligotrophic according to the Carlson index. The other lakes of the study were assigned values for trophic state which are somewhere between those assigned to Beaver Pond and Ollalie lakes. The 10 lakes studied for this report were compared to lakes studied for the compilation of the Western Lake survey (Landers, et. al. 1987). It was noted that Beaver Pond, Round, and Sportsman lakes are nutrient rich while Monon, Ollalie, and Gifford, are nutrient poor when compared to other lakes located in the Pacific Northwest. Anvil, Cripple Creek, Fish, and Rimrock lakes have profiles consistent with the majority of mountain lakes located in the area.
2

Soil Properties and Behavior of Earthflows in the Mt. Hood National Forest, Oregon

Smith, Douglas Andrew 19 April 1994 (has links)
Soils from two active earthflows, two earthflow deposits, and three non-earthflow landforms are examined to determine if a connection exists between near-surface soil properties and rates of earthflow movement. The study area is located in the Clackamas Ranger District of the Mt. Hood National Forest in the northern Oregon Cascades. Its geology consists of clay-bearing volcaniclastic formations overlain by unaltered flows of andesite and basalt, a combination that contributed to large-scale landsliding during the late Pleistocene. Deposits from these landslides now cover much of the valley floor, and it is from these deposits that earthflows tend to mobilize. The main hypothesis is that near-surface soil properties reflect earthflow movement and may be used to distinguish between active and inactive earthflows. The results support this hypothesis and indicate that soils in each of the three categories show clear differences in terms of their physical properties. The mean field moisture content of active earthflows is 56 percent, while that of earthflow deposits is 46 percent and that of non-earthflow landforms is 36 percent. All samples from active earthflows exhibit plasticity, whereas 90 percent of samples from earthflow deposits and only 25 percent of samples from nonearthflow landforms exhibit plasticity. The mean liquid limit of active earthflows is 78 percent, compared to 60 percent for earthflow deposits and 46 percent for non-earthflow landforms. The mean plasticity index of active earthflows is 41 percent, compared to only 13 percent for earthflow deposits and non-earthflow landforms. These differences are largely attributed to clay content and clay type. The mean clay content of active earthflows is 46 percent, compared to 24 percent for earthflow deposits and only 5 percent for nonearthflow landforms. In contrast, the mean sand content of active earthflows is 20 percent, while earthflow deposits contain 40 percent and non-earthflow landforms 50 percent. This difference in particle sizes is reflected in friction angle. Active earthflows have a mean friction angle of 15 degrees, compared to 24 degrees for earthflow deposits and 31 degrees for non-earthflow landforms. These results indicate that soil properties can be used to draw distinctions between active and inactive earthflows. However, soil properties are much less effective at distinguishing between active earthflows that move at different rates. For example, Junction earthflow, which moves only a few centimeters per year, is composed of soils that indicate it to be less stable than the Collowash earthflow, which moves approximately 2 meters per year. The reason for this discrepancy is that, in addition to soil properties, the rate of earthflow movement depends on the complimentary effects of hydrology, slope angle, toe erosion, and boundary roughness. Many ancient landslide deposits in the Mt. Hood National Forest are poised for action and may mobilize upon the slightest provocation. Since this is not seen as a "desired future condition" there is a need to differentiate between those deposits with a potential for reactivation and those likely to remain dormant. Examining the physical properties of soils appears to be one way to do this, and the information collected is valuable to land managers and earth scientists alike.
3

An Examination of Commercial Medicinal Plant Harvests, Mount Hood National Forest, Oregon

Campbell, Shannon Michelle 01 January 2000 (has links)
During the past fifteen years, non-timber or special forest products have become an important economic resource in the Pacific Northwest. These products are primarily derived from understory species and contribute approximately $200 million to the regional economy. Medicinal plants are a little researched component of the non-timber forest product industry that relies on cultivated and wildcrafted (or wild-collected) medicinal plant species. This study examines the commercial extraction of wildcrafted medicinal plants from Mount Hood National Forest. Specifically, this study documents the medicinal plant species extracted from Mount Hood National Forest, their annual yield amounts, harvesting methods, and the changes in cover of target species after harvest. This research uses survey data obtained from employees of two herbal companies and representatives of the U.S. Forest Service to describe medicinal plant extraction and administration as it pertains to the commercial extraction of plant species from Mount Hood National Forest. Field data were also used to examine changes in plant cover for four medicinal plant species (kinnikinnick, yarrow, Oregon grape and valerian) following harvest. Field results indicate that medicinal plant cover decreased significantly in all but one harvested sampling unit. Permanent unit markers were established at all the study sites to provide opportunities for long-term monitoring of target species responses to harvest. Eleven medicinal plant species are commonly collected for commercial purposes from Mount Hood National Forest. The general lack of regulation and enforcement of commercial medicinal plant extraction coupled with an increasing demand for wildcrafted medicinal plants warrant a need for increased collaboration between regulatory agencies, herbal companies, and the general public. Additional management and research recommendations regarding the ecological impacts of medicinal plant removal are also presented.
4

Seeing the Forest for the Roads: Auto-Tourism and Wilderness Preservation in Mount Hood National Forest, 1913-64

Rose, Taylor Elliott 28 November 2016 (has links)
Between 1913 and 1964, automobile roads appeared throughout the Cascade Mountains around Mount Hood, just east of Portland, Oregon. From elaborate scenic highways to primitive dirt trails, each had its own story. Many of them are gone today, decommissioned and decomposing with the rotting understory soil of the forest. However, some remain as the most utilized spaces in Mount Hood National Forest, one of the most popular public land units for recreation in the country, owned and managed by the United States Forest Service. "Seeing the Forest for the Roads" uncovers the history of why roads were built, who planned them, and how they were used. At the same time, it seeks to answer the question, how do roads shape the way that people view wild nature? As places that are simultaneously easily accessible and "untrammeled," wilderness has much to do with roads. But it has even more to do with the people that envisioned, constructed, and used the roads. The story that follows is divided into four sections, from the Progressive Era, through the Roaring Twenties, New Deal years, and into the mid-twentieth century. It concludes with the Wilderness Act of 1964, a profound, important statement about the relationship between technology, nature, and human beings, which singled out roads as the most visible, damaging threat to the existence of wilderness as modern Americans know it. I argue that in order to understand wilderness as both a legal term and a social construct, scholars must look at the roads themselves, particularly from a local, on-the-ground perspective. In the end, what results is a more nuanced understanding of the twentieth-century history of technology and nature, as well as the social, cultural, and intellectual context that produced both sides of the same coin in wilderness.
5

Current and future economic impact of Mount Hood National Forest outdoor recreation consumption /

Anderson, David M January 1991 (has links)
Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 80-89). Also available on the World Wide Web.
6

Ambivalent Landscapes: An Historical Geography of Recreation and Tourism on Mount Hood, Oregon

Mitchell, Ryan Franklin 01 June 2005 (has links)
Mount Hood is an Oregon icon. The mountain has as long and rich a history of recreation and tourism as almost any other place in the American West. But contemporary landscapes on Mount Hood reveal a recreation and tourism industry that has struggled to assert itself, and a distinct geographic divide is evident in the manner in which tourism has been developed. Why? In this study I chronicle the historical geography of recreation and tourism on Mount Hood. I examine the evolution of its character and pattern, and the ways in which various communities have used it to invest meaning in the places they call home. Despite the efforts of early boosters, Mount Hood has never been home to an elite destination resort like Aspen, Sun Valley, or Vail. Instead, modest recreation developed alongside timber and agriculture, and today the area is primarily a regional attraction. Unlike destinations with national and international clienteles that play a significant role in shaping lives and landscapes, local and regional interests are the primary drivers of recreation and tourism on Mount Hood. Communities on the mountain have incorporated the industry into their lives and landscapes to varying degrees. Mount Hood is also inextricably tied to Portland, and as an integral part of the city's history and identity, reflects its residents' tastes, values, and priorities. This combination of local and metropolitan interests has left an imprint on Mount Hood that reflects tensions and contradictions that define Oregon in the early twenty-first century: past vs. future, old vs. new economies, urban vs. rural inclinations, progress vs. status quo, and upscale vs. modest tastes. Spatially, temporally, and psychologically, Mount Hood straddles the divide between two visions: a service-based economy in the Willamette Valley, heavily dependent on technology, and a traditional, resource-based economy in much of the rest of the state.
7

THE IMPACT OF MELTING GLACIERS ON MOUNTAIN GROUNDWATER SYSTEMS: A MULTI-YEAR STUDY INCORPORATING ISOTOPIC TRACERS AND MICROBIOLOGY IN MOUNT HOOD NATIONAL FOREST, OREGON, AND GLACIER NATIONAL PARK, MONTANA, AND TIME SERIES ANALYSES IN THE SWISS ALPS

Jordyn B Miller (11852195) 17 December 2021 (has links)
<p>Alpine glaciers around the world are in retreat and are unlikely to reverse course. This dissertation focuses on improving our understanding of the impact of glacial melt on mountainous alpine groundwater systems. Studies on glacial melt-groundwater interactions have become more prevalent, particularly in the past 5 years, because we are recognizing that the contribution of glacial melt to the hydrologic cycle is not limited to melt-season surficial streamflow. The importance of glacial melt to mountain groundwater systems has the potential to not only influence spring and streamflow generation, but also the longevity of alpine specific, and frequently endangered species, dependent on this source of recharge. This recharge may be vital for human water needs such as potable water, agriculture, and hydrothermal power.</p>The impact that a transition from glacial melt to snow- or rain-dominated streamflow and recharge will have on alpine ecosystems in a continually warming climate is far reaching. This dissertation: 1) tests whether glacial melt is an important source of recharge for mountain springs and their microbial communities, 2) investigates the spatial impact of glacial-melt recharge on residence times and flowpaths that support alpine springs, and 3) explores the impact of post-peak water on alpine baseflow using a statistical, timeseries approach. My results show that the groundwater systems in glaciated mountainous, alpine regions are particularly vulnerable to climate change. Springs in Mount Hood National Forest and Glacier National Park were sampled over a 4-year period, and in addition, publicly available long-term streamflow datasets were are also utilized. The chapters composing this work build upon each other, and compare and contrast the factors most important in glacial melt recharging the mountain-block. Information that is vital to the management of alpine water resources by landowners, watershed groups, scientists, and others interested in mountain groundwater systems in glaciated alpine regions is presented in the following pages.

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