Showing items related by title, author, creator and subject.

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  Twentieth century fire patterns in the Gila/Aldo Leopold Wilderness areas, New Mexico and the Selway-Bitterroot Wilderness area, Idaho/Montana

  Rollins, Matthew Gregory (The University of Arizona., 2000)

  I used archives of wildfire perimeters (fire atlases) within a geographic information system (GIS) to describe and evaluate fire frequency patterns for the 20th century in the 486,673-ha Gila/Aldo Leopold Wilderness Complex (GALWC), New Mexico and the 785,090-ha Selway-Bitterroot Wilderness Complex (SBWC) in Idaho and Montana. I addressed questions about changing 20th century fire frequencies and landscape-scale controls of fire frequency by analyzing fire atlases along with data for topography, vegetation, and climate. Similarities and differences in comparisons between study areas highlight important aspects of fire regimes and strengthen my interpretation and inference. In the GALWC, fire rotations were shortest during the recent wildfire use period (1975-1993) and longest during the pre-modern suppression period (1909-1946). In the SBWC, fire rotations were shortest during the pre-modern suppression period (1880-1934) and longest during the modern suppression period (1935-1975). Elevations with the highest fire frequencies differed between study areas. However, forest types found at these elevations are characterized by similar overstory tree species. Steeper northeastern slopes in the GALWC and southwestern slopes in the SBWC burned most frequently. I assert that, in the GALWC, horizontal fuel continuity is a main factor determining fire frequency. In the SBWC, fuel moisture status limits fire frequency. Fires are most frequent in areas where ignitions occur and neither fuel continuity nor fuel moisture are likely to limit fire spread. Three statistical modeling approaches were used to produce maps of reburn probabilities. Log-likelihood modeling provided the most satisfactory results, while logistic regression and classification and regression trees yielded statistically insignificant models. Empirical models contributed to the assertion that fuel continuity limits fire frequency in the GALWC while fuel moisture limits fire frequency in the SBWC. Mapped fire perimeters provide a valuable source of spatial historical information for describing the role of large fires over broad areas. This dissertation enhances scientific knowledge about broad scale changes in fire regimes. Comparisons between areas facilitate identification of unique versus general patterns. Results provide a contemporary baseline for comparison with estimates of Pre-EuroAmerican fire frequencies, and a historical, spatial context for modeling and managing future fire regimes.
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  Perception of desert wilderness by the Superstition Wilderness user

  Lewis, Jeffrey William, 1946- (The University of Arizona., 1971)
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  Perspectives on Rock Climbing Fixed Anchors Through the Lens of the Wilderness Act: Social, Legal and Environmental Implications at Joshua Tree National Park, California

  Murdock, Erik Daniel (The University of Arizona., 2010)

  The issue of fixed anchors in wilderness challenges modern interpretations of the Wilderness Act. The Wilderness Act can be interpreted to allow or preclude the placement of fixed anchors in designated wilderness areas depending on whether the interpreter chooses a literal or general interpretation of the law's meaning. Place-based management options, supported by descriptive and evaluative study results, may be more closely aligned to Wilderness Act directives than nationwide, blanket policy. This research is focused on understanding the role of fixed anchors in designated wilderness in order to develop management options that protect wilderness values without hindering wilderness users. The unique nature of each wilderness area and climbing resource, in combination with distinct preferences and motivations of different climber populations, lends itself to managing fixed anchors through place-based policy that considers the landscape and the preferences of individual visitors.Joshua Tree National Park [JTNP] was chosen as the location for this case study because it has committed to establishing fixed anchor management that accommodates rock climbing and protects wilderness resources. JTNP has prohibited the placement of fixed anchors in wilderness since February 1993. By combining resource inventories, spatial modeling, and wilderness climber profiles, study results reveal that wilderness visitor destination choice is not dependent on the location of fixed anchors, but the quality, difficulty, and distance to destinations. These results can be used as the basis for a wilderness fixed anchor permit system and demonstrate that fixed anchors can fit within the confines of the Wilderness Act. Place-based management options, relative to national policies, can minimize administrative burdens and limit the geographic extent of unintended regulatory effects. The Wilderness Act's minimum administrative requirement mandate promotes this type of management style. This study of the benign fixed anchor at JTNP illustrates the power of the scientific method to neutralize wilderness recreation conflict and support streamlined wilderness management, while at the same time highlighting the shortcomings, and strengths, of the Wilderness Act as it is applied to a new era of wilderness recreation management.