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

Persistent Link:
http://hdl.handle.net/10150/284205
Title:
Twentieth century fire patterns in the Gila/Aldo Leopold Wilderness areas, New Mexico and the Selway-Bitterroot Wilderness area, Idaho/Montana
Author:
Rollins, Matthew Gregory
Issue Date:
2000
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
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.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture, Forestry and Wildlife.; Environmental Sciences.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Renewable Natural Resources
Degree Grantor:
University of Arizona
Advisor:
Swetnam, Thomas W.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleTwentieth century fire patterns in the Gila/Aldo Leopold Wilderness areas, New Mexico and the Selway-Bitterroot Wilderness area, Idaho/Montanaen_US
dc.creatorRollins, Matthew Gregoryen_US
dc.contributor.authorRollins, Matthew Gregoryen_US
dc.date.issued2000en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractI 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.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgriculture, Forestry and Wildlife.en_US
dc.subjectEnvironmental Sciences.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineRenewable Natural Resourcesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSwetnam, Thomas W.en_US
dc.identifier.proquest9983884en_US
dc.identifier.bibrecord.b40825176en_US
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