@mastersthesis {494, title = {Spatial and temporal validation of fire-scar fire histories}, volume = {PhD}, year = {2009}, school = {University of Arizona}, abstract = {

Accurate information about historical fire regimes is needed to understand the long-term effects of fire and climate on ecosystem dynamics and guide ecosystem restoration. Fire scars are used widely to reconstruct historical fire regimes around the world but few empirical validation studies have been conducted. This dissertation consists of three integrated studies aimed at addressing the following questions: (1) how accurate are fire-scar fire histories compared to known patterns of fire occurrence; (2) how do these relationships vary spatially and temporally; (3) how representative statistically are search-based (\“targeted\”) fire-scar sampling techniques? I utilized an empirical corroboration approach to validate fire-scar reconstructions against documentary fire perimeters for a 2,780 hectare ponderosa pine landscape in Saguaro National Park, Arizona (USA). Resampling statistics and spatial modeling were used to quantify interactions between spatial scale, sample size, and fire size. Statistical properties of targeted sampling were assessed by analyzing three case studies containing paired examples of targeted and non-targeted sampling (i.e., systematic and census). I found strong linear relationships between fire-scar synchrony (samples scarred in a given year) and annual area burned. Fire-scar derived estimates of fire frequency metrics, such as Mean Fire Return Interval and Natural Fire Rotation, did not differ significantly from the documentary record, and there was strong spatial coherence between fire frequency maps interpolated from fire-scar data and documentary maps. Scale and sample size dependence of fire-scar detection probabilities were variable for small fire years but relatively weak for widespread fires. This resulted in consistent and predictable influences on fire frequency reconstructions: statistical measures dependent on area burned were relatively stable and robust across a range of scale, sample size, and fire size. Targeted sampling did not differ statistically from non-targeted datasets, but targeted fire-scar data contained proportionately greater sample depth and longer temporal records with fewer samples. These results demonstrate collectively that key temporal and spatial fire frequency parameters can be reconstructed accurately from point-based fire-scar data. They also reaffirm general interpretations and management implications from past fire history research indicating that frequent, widespread burning was an important component of pre-settlement fire regimes in Southwestern ponderosa pine.

}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=1937808421\&sid=2\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Farris, Calvin Arthur} } @mastersthesis {842, title = {Fire History and Fire Climate Relationships in Upper Elevation Forests of the Southwestern United States}, volume = {Ph.D}, year = {2007}, note = {

Please contact the Laboratory of Tree Ring Research for a copy of this dissertation. The file is too large to be uploaded at this time.

}, pages = {182}, school = {University of Arizona}, type = {Dissertation}, address = {Tucson}, abstract = {

Fire history and fire-climate relationships of upper elevation forests of the southwestern United States are imperative for informing management decisions in the face of increased crown fire occurrence and climate change. I used dendroecological techniques to reconstruct fires and stand-replacing fire patch size in Madrean Sky Islands and Mogollon Plateau. Reconstructed patch size (1685-1904) was compared with contemporary patch size (1996-2004). Reconstructed fires at three sites had stand-replacing patches totaling \> 500 ha. No historical stand-replacing fire patches were evident in the mixed conifer/aspen forests of the Sky Islands. Maximum stand-replacing fire patch size of modern fires (1129 ha) was greater than that reconstructed from aspen (286 ha) and spruce-fir (521 ha). Updated spruce-fir patches may be evidence of larger (\>2000ha) stand-replacing fire patches.

To provide climatological context for fire history I used correlation and regionalization analyses to document spatial and temporal variability in climate regions, and El-Nino Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multi-decadal Oscillation (AMO) teleconnections using 273 tree-ring chronologies (1732-1979). Four regions were determined by common variability in annual ring width. The component time score series replicate spatial variability in 20th century droughts (e.g., 1950\’s) and pluvials (e.g., 1910\’s). Two regions were significantly correlated with instrumental SOI and AMO, and three with PDO. Sub-regions within the southwestern U.S. varied geographically between the instrumental (1900-1979) and the pre-instrumental periods (1732-1899). Mapped correlations between ENSO, PDO and AMO, and tree-ring indices illustrate detailed sub-regional variability in teleconnections.

I analyzed climate teleconnections, and fire-climate relationships of historical upper elevation fires from 16 sites in 8 mountain ranges. I tested for links between Palmer Drought Severity Index and tree-ring reconstructed ENSO, PDO and AMO phases (1905-1978 and 1700-1904). Upper elevation fires (115 fires, 84 fire years, 1623-1904) were compared with climate indices. ENSO, PDO, and AMO affected regional PDSI, but AMO and PDO teleconnections changed between periods. Fire occurrence was significantly related to inter-annual variability in PDSI, precipitation, ENSO, and phase combinations of ENSO and PDO, but not AMO (1700-1904). Reduced upper elevation fire (1785-1840) was coincident with a cool AMO phase.

}, keywords = {AMO, climate, dendrochronology, dendroclimatology, ENSO, environment, fire, fire history, forest, madrean sky islands, mogollon plateau, mountain, PDO, southwest, teleconnection, tree ring, upper elevation, Watershed Management}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=1375523671\&sid=1\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD.}, author = {Margolis, Ellis Quinn} } @mastersthesis {514, title = {Landscape Fire History and Age Structure Patterns in the Sky Islands of Southeastern Arizona}, volume = {PhD}, year = {2006}, school = {University of Arizona}, abstract = {At regional scales climate patterns (e.g., interannual wet-dry cycles) result in high spatial fire synchrony among Southwest forests. However, in the {\textquotedblleft}Sky Island{\textquotedblright} forests of southeastern Arizona spatial and temporal patterns of fire history and tree age structure at landscape levels (i.e., within mountain ranges) are relatively unknown and therefore the focus of this study. In the Santa Catalina Mountains we reconstructed the fire history on a 2,900-hectare study area with two distinct landscapes, Butterfly Peak (BP) and Rose Canyon (RC) using 2-hectare {\textquotedblleft}points{\textquotedblright} (i.e., collection areas). The RC landscape was dominated by shallow south-facing aspects and BP was dominated by steep north-facing aspects. Within each landscape, point mean fire intervals (PMFIs) were not significantly different between aspect classes. However, pooled PMFIs were significantly shorter in RC compared to BP. These results show that the fire history at any given point (i.e., 2 hectares or less) was primarily controlled by the broad-scale topography of the encompassing landscape, rather than by the fine-scale topography at that point. Using similar methods we also reconstructed the fire history on Rincon Peak, which is a small isolated mountain range with very step topography. The fire history of the 310-hectare forest area was a mixture of frequent low severity surface fires (from AD 1648 to 1763) and infrequent mixed-severity fires (from AD 1763 to 1867). This mixed-fire regime was probably due to a combination of climatic variability, the small area and rugged topography of this mountain range, and complex fuel arrangements. The distinct fire histories from these two study areas provided natural age structure experiments that indicated tree age cohorts (i.e., higher than expected tree establishment pulses) occurred during periods of reduced fire frequencies. In some instances these periods were likely caused by climatic variability (e.g., a wet and/or cool early 1800s) creating synchronous age cohorts across the region. At other times, extended fire intervals were a function of local topography (e.g., 1763-1819 in the northern half of Rincon Peak). Overall, these studies demonstrated that landscape and climatic variations combine to produce complex spatial and temporal variations in fire history and tree age structures.}, keywords = {Renewable Natural Resources}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=1144189411\&sid=5\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Iniguez, Jose M.} } @mastersthesis {493, title = {Scaling Rules for Fire Regimes}, volume = {PhD}, year = {2004}, school = {University of Arizona}, abstract = {Forest fire is a keystone ecological process in coniferous forests of southwestern North America. This dissertation examines a fire regime in the Jemez Mountains of northern New Mexico, USA, based on an original data set collected from Monument Canyon Research Natural Area (MCN). First, I examine scale dependence in the fire regime. Statistical descriptors of the fire regime, such as fire frequency and mean fire interval, are scale-dependent. I describe the theory of the event-area (EA) relationship , analogous to the species-area relationship, for events distributed in space and time; the interval-area (IA) relationship , is a related form for fire intervals. The EA and IA also allow estimation of the annual fire frame (AFF), the area within which fire occurs annually on average. The slope of the EA is a metric of spatio-temporal synchrony of events across multiple spatial scales. The second chapter concerns the temporal distribution of fire events. I outline a theory of fire interval probability from first principles in fire ecology and statistics. Fires are conditional events resulting from interaction of multiple contingent factors that must be satisfied for an event to occur. Outcomes of this kind represent a multiplicative process for which a lognormal model is the limiting distribution. I examine the application of this framework to two probability models, the Weibull and lognormal distributions, which can be used to characterize the distribution of fire intervals over time. The final chapter addresses the theory and effects of sample size in fire history. Analytical methods (including composite fire records) are used in fire history to minimize error in inference. I describe a theory of the collector{\textquoteright}s curve based on accumulation of sets of discrete events and the probability of recording a fire as a function of sample size. I propose a nonlinear regression method for the Monument Canyon data set to correct for differences in sample size among composite fire records. All measures of the fire regime reflected sensitivity to sample size, but these differences can be corrected in part by applying the regression correction, which can increase confidence in quantitative estimates of the fire regime.}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=845727371\&sid=3\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Falk, Donald Albert} } @mastersthesis {521, title = {Fire-Climate-Vegetation Interactions in Subalpine Forests of the Selway-Bitterroot Wilderness Area, Idaho and Montana, USA}, volume = {PhD}, year = {2003}, school = {University of Arizona}, abstract = {The long term patterns of fire-climate interactions and forest recovery processes in subalpine forests are poorly understood. This study used a suite of dendrochronological techniques to identify tree growth-climate relationships, assess the interactions of fire with interannual climate variability, and reconstruct summer temperature in subalpine forests of the Selway-Bitterroot Wilderness Area on the border of Idaho and Montana, USA. Comparison of ring-width chronologies from whitebark pine ( Pinus albicaulis Engelm.) and subalpine larch ( Larix lyallii Parl.) with modern climate data indicated that summer temperatures were most limiting to growth in these conifers. Warm summers were generally conducive to radial growth. However, the temporal stability of the climate-tree growth relationship weakens from the early to later periods of the record. Alterations to growing season length, possibly modified by snow pack, may be related to the reduction in climate-growth relationships. A 748-year reconstruction of average summer temperature was developed that explains [approximate]36\% of the variance of the instrumental record. Positive values of the coefficient of efficiency and reduction of error verification statistics indicated that the reconstruction was of good quality. Warm and cool periods in the reconstruction include a warm decade around the 1650s and prolonged cooling around 1700. Peaks in variance in reconstructed average summer temperature occurred at 87, 15, and 2 years. More than 2000 fire scar and age structure samples were used to evaluate fire-climate relationships. Comparison of widespread fire events to climate variables indicated dry conditions both during the fire year and one year before a fire. Multiple spatial patterns of drought and El Ni{\~n}o were related to widespread fire occurrence. Forest recovery following fires generally proceeds from lodgepole pine ( Pinus contorta var. latifolia Dougl.) toward spruce-fir forests ( Picea engelmannii Parry- Abies lasiocarpa (Hook) Nutt.). Two successional pathways occur, one beginning with an initial lodgepole pine stage, the other a spruce-fir stage. Initial composition was related to the presence of overstory lodgepole pine at the time of fire occurrence as well as the intervals between successive fires. Collectively, these results suggest a strong multi-year drought linkage between climate and fire, and dependence on fire intervals for structuring forest communities.}, keywords = {Geography}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=765957031\&sid=4\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Kipfmueller, Kurt Foster} } @mastersthesis {910, title = {Stand Replacing Fire History and Aspen Ecology in the Upper Rio Grande Basin}, volume = {Master of Science}, year = {2003}, pages = {94}, school = {University of Arizona}, address = {Tucson}, abstract = {

Dendroecological techniques were applied to reconstruct stand-replacing fire history in mixed conifer and spruce-fir forests in northern New Mexico and southern Colorado. Stand-replacing fire dates with annual accuracy and precision were determined using four lines of evidence for each of twelve sites within a 75,000 square kilometer area. The four lines of evidence were: (1) aspen inner-ring dates, (2) conifer death dates, (3) tree-ring width changes, or other morphological indicators of injury, and (4) fire scars. The annual precision of dating allowed the identification of significant synchrony of stand replacing fires among the 12 sites and regional surface fire events previously reconstructed from the large network of fire scar collections in the Southwest. Nearly all of these synchronous stand-replacing and surface fire years coincided with extreme droughts. This suggests that stand-replacing fire activity occurred primarily when drought conditions allowed fires to ignite and spread within these high elevation forests and/or for the spread of surface fires between lower and upper elevations. Fifty percent of reconstructed stand-replacing fires pre-dated large-scale Euro-American settlement in this region. This may suggest that land use practices (such as logging and mining) were not as important in promoting stand-replacing fires in these study sites, as compared with other areas in Colorado.

}, keywords = {aspen, basin, colorado, conifer, dendrochronology, dendroecology, Ecology, fire, fire history, new mexico, rio grande, spruce fir, stand replacing, tree ring}, author = {Margolis, Ellis Quinn} } @mastersthesis {506, title = {Effects of Substrate on Dendrochronologic Streamflow Reconstruction: Paria River, Utah; With Fractal Applications to Dendrochronology}, volume = {PhD}, year = {2002}, school = {University of Arizona}, abstract = {Two pi{\~n}on ( Pinus edulus ) tree-ring chronologies developed on each of three substrates (sandstone, shale, and alluvial fan deposits) in southern Utah for the period 1702 to 1997 demonstrate that geologic substrate affects dendrochronologic streamflow reconstructions. Chronologies from alluvial fan deposits explain the most variance of cool-season (October 1 to May 31) flow with an adjusted coefficient of determination (R a 2 ) equal to 0.59. Chronologies from sandstone deposits account for 52 percent of the variance, while those on shale deposits account for 45 percent. The highest single-site annual discharge reconstruction (October 1 to September 30), R a 2 = 0.25, is provided by chronologies from shale deposits. The highest substrate-pair annual discharge reconstruction, R a 2 = 0.27, is provided by chronologies from alluvial fan deposits. The highest summer discharge reconstruction (July 4 to September 3), R a 2 = 0.14, is provided by chronologies from sandstone. The different substrate response is attributed to varying amounts of clay in each substrate affecting infiltration and available water for tree growth. The fractal parameters (fractal dimension and Hurst exponent), calculated using the roughness-length method, describe the long-term persistence of each tree-ring series and of the hydrologic record. The fractal dimensions range from 1.739 to 1.939 for the tree-ring series for the calibration period, and from 1.884 to 1.946 for the entire chronology periods. The fractal dimension for the annual hydrologic record is 1.802, and 1.819 from October 1 through May 31. Modification of each tree-ring series based on the ratios of the Hurst exponent of each series forced the fractal dimensions of the tree-ring series to be closer to that of the hydrologic series. (Abstract shortened by UMI.)}, keywords = {Watershed Management}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=765129271\&sid=4\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Grow, David Earl} } @mastersthesis {558, title = {Tree-Ring Reconstruction of Western Spruce Budworm Outbreaks in the Rio Grande National Forest, Colorado}, volume = {Master of Science}, year = {1999}, pages = {97}, school = {University of Arizona}, address = {Tucson}, abstract = {

Tree-ring records were used to reconstruct the spatial and temporal patterns of western spruce budworm (Choristoneura occidentalis Freeman) outbreaks in the Rio Grande National Forest (RGNF) of southern Colorado. Reconstructions at 11 host stands showed a synchronous pattern of outbreaks with a peak in the number of trees recording outbreaks over the entire RGNF on average every 24 years. These synchronous periods of outbreaks coincided with periods of increased moisture as indicated by an independently reconstructed summer Palmer Drought Severity Index, while relatively few trees recorded outbreaks during dry periods. The reconstruction on the RGNF does not support the hypothesis that human land use has significantly altered outbreak patterns. Tree response to outbreaks in the RGNF was different from prior studies as reductions in the growth were typically detectable only when growth was compared to that of nonhost tree species.

}, keywords = {colorado, dendrochronology, department of agriculture, forest service, national forest, outbreak, palmer drought severity index, RGNF, rio grande, tree ring, western spruce budworm}, author = {Ryerson, Daniel E.} } @mastersthesis {478, title = {Fire history and stand structure in the Huachuca Mountains of Southeastern Arizona}, volume = {MS}, year = {1998}, school = {University of Arizona}, abstract = {Historically, wildfires in mixed conifer forests of Southwestern sky islands were frequent events. Dendrochronological methods were used to reconstruct fire regimes and stand age structures in the Huachuca Mountains of Southeastern Arizona. Pre-settlement (i.e., before ca. 1870) fire intervals ranged from 4 to 10 years, with many fires spreading over the entire sample area. Stand age distributions show an increase in more shade-tolerant tree species. Although ponderosa pine is still the dominant overstory tree species, recent recruitment is predominantly southwestern white pine and Douglas-fir. Establishment of Ft. Huachuca in 1877 was a precursor to extensive use of timber, mineral, range and water resources in the Huachuca Mountains. The fire regime was altered at this time, with only one subsequent widespread surface fire recorded in 1899. Settlement era land-use practices may be responsible for changes in stand structure and composition.}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=738257621\&sid=3\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Danzer, Shelley Rae} } @mastersthesis {516, title = {Fire History in Riparian Canyon Pine-Oak Forests and the Intervening Desert Grasslands of the Southwest Borderlands: A Dendroecological, Historical, and Cultural Inquiry}, volume = {MS}, year = {1998}, school = {University of Arizona}, address = {Tucson}, abstract = {

Dendroecological, documentary, and ethnoecological evidence were combined to provide an integrated understanding of past natural and cultural fires in the Southwest Borderlands. Fire frequency for the desert grasslands was inferred from synchronous intercanyon fire events. Mean fire intervals range between 4-8 years in canyon pine-oak forests, 4-9 years in the intervening desert grasslands, and 5-9 years in the mixed-conifer forests. Riparian canyon pine-oak forests were important corridors for fire spread between the desert grasslands and higher-elevation forests. The decline of post-settlement (\>1870s) fires typical of most forests in U.S., is not evident south of the border in Mexico.

Documentary evidence reveals the Apache had detailed knowledge of fire, that burning practices were controlled and limited, and ecosystem enhancement through intentional burning was not suggested. However, the common exception was burning practiced during wartime periods, principally by the Apache but also by the Spanish, Mexicans, and later Americans. Fire reconstructions indicate that wartime-period fires were significantly more frequent than peacetime periods at several canyon-rancher{\'I}a sites.

}, keywords = {apache, borderland, cultural, dendrochronology, dendroecological, desert grassland, ethnoecological, fire, fire history, historical, Mexico, oak, peacetime, pine, post settlement, riparian, southwest, spanish, wartime, Watershed Management}, author = {Kaib, J. Mark} } @mastersthesis {439, title = {Fire Histories of Upper Elevation Forests in the Gila Wilderness, New Mexico via Fire Scar and Stand Age Structure Analyses}, volume = {Master of Science}, year = {1997}, pages = {120}, school = {University of Arizona}, address = {Tucson}, abstract = {

Fire-scar analysis to identify fire events and stand age structure analysis to identify fire effects on survivorship of trees were used to reconstruct surface and crown fire regimes in upper elevation forests of the Gila Wilderness, NM. Fire regimes varied across forest type, but not necessarily across elevation. Prior to the twentieth century, (from 1706 to 1904), the mean interval for large fires was 8 years. During the twentieth century, (from 1904 to 1995), the mean fire return interval for large fires was 46 years. The virtual end of historically frequent fire regimes due to livestock grazing and fire suppression since the turn of the century has affected successional pathways of forest types across elevations, favoring later successional forest species and structures.

}, keywords = {dendrochronology, fire, fire regime, fire scar, gila wilderness, new mexico, stand age, suppression, tree ring, upper elevation}, author = {Abolt,Rena Ann Peck} } @mastersthesis {585, title = {Reconstruction of historical fire regimes along an elevation and vegetation gradient in the Sacramento Mountains, New Mexico}, volume = {MS}, year = {1997}, school = {University of Arizona}, abstract = {The purpose of this study was to reconstruct historical fire regimes along an elevation and vegetation gradient in the Sacramento Mountains, NM. I cross-dated fire-scarred specimens to reconstruct the fire history within two mixed-conifer, four ponderosa pine, and two pinon-juniper stands. Prior to Euro-American settlement, historical fire intervals were estimated at 6 years in ponderosa pine, 10 years in mixed-conifer, and 27 years in pinon-juniper forests. To evaluate whether Native Americans may have influenced historical fire regimes, I cross-dated scars from peeled trees found within the study area. Comparison between scar dates, historical records, and variations in fire frequencies did not show a regional effect on historical fire regimes by Mescalero, but suggested that they may have had a local impact on fire frequencies of the late 1700{\textquoteright}s. Following Euro-American settlement (ca. 1880) fire was nearly absent from the study area due to livestock grazing and fire suppression.}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=738180921\&sid=4\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Wilkinson, Margot Carolina} } @mastersthesis {538, title = {Reconstruction and Interpretation of Historical Patterns of Fire Occurrence in the Organ Mountains, New Mexico}, volume = {Master of Science}, year = {1996}, pages = {144}, school = {University of Arizona}, address = {Tucson}, abstract = {

The purpose of this research was to reconstruct and interpret the history of fire in the Organ Mountains, New Mexico. I used dendrochronological techniques to date fire scars on 90 trees comprising ten sites within the Fillmore Canyon watershed. Two fire regimes were identified during the pre-settlement period. Fire Regime I, 1650-1805, was characterized by a high fire frequency (ca. once every two years) and a predominance of patchy fires. Fire Regime II, 1805-1874, was characterized by a lower fire frequency (ca. once every 3.5 years) and a predominance of widespread fires. During the post-settlement period fire was virtually non-existent. I hypothesize that Apache use-of-fire influenced patterns during the pre-settlement period, while Euro-American land use activities influenced patterns during the post-settlement period. Fire-precipitation associations suggest that low fuel moisture levels were a pre-condition for widespread fires.

}, keywords = {dendrochronology, fillmore canyon, fire, Geography, historical, new mexico, organ mountains, reconstruction}, author = {Morino, Kiyomi Ann} } @mastersthesis {550, title = {A Dendroecological Assessment of Whitebark Pine in the Sawtooth Salmon River Region Idaho}, volume = {Master of Science}, year = {1995}, pages = {56}, school = {University of Arizona}, address = {Tucson}, abstract = {

Whitebark pine (Pinus albicaulis Engelm.) tree-ring chronologies of 700 to greater than 1,000 years in length were developed for four sites in the Sawtooth-Salmon River region, central Idaho. These ring-width chronologies are used to (1) assess the dendrochronological characteristics of this species, (2) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonus ponderosae Hopk.) epidemic during the 1909 to 1940 period, and (3) establish the response of whitebark pine tree ring-width growth to climate variables. Crossdating of whitebark pine tree-ring width patterns was verified. Ring-width indices had low mean sensitivity (0.123-0.174) typical of high elevation conifers in western North America, and variable first order autocorrelation (0.206-0.551). Mortality of dominant whitebark pine caused by mountain pine beetle had a maxima at 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above average radial growth is positively correlated with winter and spring precipitation and inversely correlated with April temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

}, keywords = {dendrochronology, dendroclimatology, dendroctonus ponderosae, dendroecology, idaho, pine beetle, pinus albicaulis, sawtooth salmon river, tree ring, whitebark pine}, author = {Perkins, Dana Lee} } @mastersthesis {504, title = {Tree-Ring Reconstructions of Climate and Fire History at El Malpais National Monument, New Mexico}, volume = {PhD}, year = {1995}, school = {University of Arizona}, abstract = {The purpose of this research was to: (1) reconstruct climate for the malpais region from long-lived trees and remnant wood; (2) reconstruct the fire history of forests in the malpais; and (3) investigate short-term and long-term relationships between wildfire and climate. To reconstruct climate, I calibrated a 2,129 year long tree-ring chronology (136 BC-AD 1992) with annual rainfall (previous July to current July). Since AD 100, seven major long-term trends in rainfall occurred. Above normal rainfall occurred during AD 81-257, 521-660, 1024-1398 and 1791-1992, while below normal rainfall occurred during AD 258-520, 661-1023 and 1399-1790. The prolonged drought from AD 258-520 was unsurpassed in its intensity, while rainfall during the most recent 200 years has exceeded any since AD 660. The reconstruction of long-term climate trends confirmed the general sequence of environmental change over the last 2,000 years for the southern Colorado Plateau. To reconstruct past fire occurrences, 217 fire-scarred trees were collected from nine sites representing the major habitat types of the malpais and dendrochronologically dated. Fire frequency was highest at sites on cinder cones and on the highly-weathered basalt flows (ca. once every five years), and lowest on the isolated kipukas and on the Hoya de Cibola Lava Flow (once every 10-12 years). Fire frequency decreased along a north to south gradient, reflecting changing vegetation properties. Combined information revealed fire occurred once every two years, while more widespread fires occurred once every 2.5 years. Fires were largely asynchronous between sites, suggesting the malpais landscape effectively hinders fire spread. Past fire history at El Malpais was characterized by four temporally distinct periods: (1) FH-1 (prior to 1782): high fire frequency, patchy fires, throughout the growing season; (2) FH-2 (1795-1880): longer fire intervals, widespread fires, mostly early season fires; (3) FH-3 (1893-1939): even longer intervals, decreased widespread fires; (4) FH4 (1940-1992): longest fire-free periods during the last 600 years. The increase in rainfall and the simultaneous change in fire regimes ca. 1790 was likely related to an increase in summer monsoonal rainfall due to changes in hemispheric circulation patterns. The decrease in fire spread ca. 1880 was most likely due to intense sheep grazing, while the change ca. 1940 reflects greater efficiency in fire suppression techniques. The presettlement fire regime emphasizes that the current absence of fire in the monument exceeds the historical range of variability established for the presettlement period. Unless effects of past human-related disturbances are mitigated, fire regimes of El Malpais will continue to favor high-intensity, catastrophic fires.}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=742088811\&sid=3\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Grissino-Mayer, Henri Dee} } @mastersthesis {540, title = {Growth responses of giant sequoia to fire and climate in Sequoia and Kings Canyon National Parks, California}, volume = {MS}, year = {1994}, school = {University of Arizona}, abstract = {I investigated the radial growth responses of giant sequoia (Sequoiadendron giganteum) to fire in Sequoia and Kings Canyon National Parks. Mean ring-width indices were used to compare growth between burned and unburned sites and between four different levels of fire severity. Mean growth increased in all sites in the post-burn periods relative to pre-burn periods. Favorable climatic conditions contributed to these growth increases. Post-fire mean growth for four out of seven burn sites, however, was significantly higher than that on unburned sites. In general, lower severity fire resulted in lower magnitude growth increases than those observed after moderate to higher severity fire. Very high severity fire that caused extensive foliage damage resulted in post-burn growth suppressions. Post-fire growth increases occurred whether post-burn years were wet or dry. Fire effects on site conditions may moderate climatic impacts on sequoia growth. Giant sequoia seedling establishment was favored by a combination of high severity fire and wet post-burn conditions.}, keywords = {Forestry}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=743039441\&sid=4\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Mutch, Linda Susan} } @mastersthesis {727, title = {An Application of Climatological Water Balance Modeling to Dendroclimatology in the Black Hills of South Dakota}, volume = {Master of Science}, year = {1993}, pages = {138}, school = {University of Arizona}, abstract = {

Tree-ring data from bur oak (Quercus macrocarpa) and ponderosa pine (Pinus ponderosa) were used to investigate the relationship between annual ring width and soil moisture in the Black Hills area of western South Dakota and eastern Wyoming. Soil moisture values were developed from a water balance model (SNWBAL), using climate data from weather stations in the area.

The response between the tree-ring chronologies and climate and water-balance variables shows a strong relation between annual ring growth and precipitation and soil moisture. The best variable combinations for reconstructing the local drought history were identified from this analysis.

Several statistical approaches were used to check the internal consistency of the data and to determine the relationship between the various data sets.

A scenario for further study, especially for the reconstruction of past climate variables was drawn based on the results of response analysis.

}, author = {Wanmei Ni} } @mastersthesis {459, title = {Dendrochronology and Fire History in a Stand of Northern California Coast Redwood}, volume = {MS}, year = {1991}, school = {University of Arizona}, abstract = {Fire-scarred cross-sections from coast redwood (Sequoia sempervirens) at two sites were dendrochronologically dated and used to develop a fire history. Redwood offers a challenge for dendrochronological study due to ring wedging and complacency. Crossdating was successful in 12 of 24 trees. The fire history was developed by comparison of fire scars and fire-associated ring characteristics (resin ducts, double latewood, growth releases, and ring separations) recorded in ring series. Using only dates of fire scars from the first fire in 1714 to the last in 1962, the mean fire interval (MFI) was 9.9 years. MFI for the best represented presettlement segment 1714-1881 was 8.0 years. Using all fire-associate ring features, MFI 1714-1962 was 7.0 years and 1714-1881, 6.0 years. Use of all fire-associated ring characteristics is argued to be a more accurate representation of past fire frequency. MFIs determined are less than others reported for coast redwood and suggest fire frequency in redwood may have been underestimated in past studies.}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=7747786571\&sid=1\&Fmt=2\&clientld=43922\&RQT=309\&Vname=PDQ}, author = {Brown, Peter Mark} } @mastersthesis {574, title = {A Dendrochronological Assessment of Western Spruce Budworm, Choristoneura Occidentalis Freeman, in the Southern Rocky Mountains}, volume = {PhD}, year = {1987}, school = {University of Arizona}, abstract = {

Tree-ring chronologies from ten mixed conifer stands in the Colorado Front Ranges and New Mexico Sangre de Cristo Mountains were used to reconstruct timing, duration, and radial growth impacts of past outbreaks of western spruce budworm, Choristoneura occidentalis Freeman. Graphical and statistical comparisons of tree-ring chronologies from host and non-host tree species, in conjunction with Forest Service records of outbreaks during the twentieth century, revealed that outbreaks were identifiable only in the host chronologies as sharply reduced growth periods. These comparisons also showed that host and non-host tree-ring chronologies were generally similar between outbreaks and that both were responding in a similar manner to climatic variation. A study of defoliation and insect population data that was available for the New Mexico stands demonstrated that host radial growth from 1978 to 1983 was highly correlated with budworm activity. The non-host chronologies from each stand were used to correct the host chronologies for climatic and other non-budworm environmental variations by a differencing procedure. The corrected chronologies were then used to estimate the dates and radial growth effects of past budworm outbreaks. Tree-ring characteristics of twentieth century documented outbreaks were used as criteria for inferring the occurrence of outbreaks in previous centuries. At least nine periods of increased budworm activity were identified in the region from 1700 to 1983. The mean duration of reduced growth periods caused by known and inferred budworm outbreaks was 12.6 years, and the mean interval between initial years of successive outbreaks was 34.9 years. The mean maximum radial growth loss was 50 percent of expected growth, and the mean periodic growth loss was 21.6 percent. There was an unusually long period of reduced budworm activity in the first few decades of the twentieth century, and since that time outbreaks have been markedly more synchronous between stands. Increased synchroneity of outbreaks in the latter half of the twentieth century suggests that areal extent of outbreaks has increased. This phenomenon may be due to changes in the age structure and species composition of forests following harvesting and fire suppression in the late nineteenth and early twentieth centuries.

}, keywords = {Watershed Management}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=753027921\&sid=16\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Swetnam, T.} } @mastersthesis {573, title = {Fire History of the Gila Wilderness, New Mexico}, volume = {Master of Science}, year = {1983}, pages = {156}, school = {University of Arizona}, address = {Tucson}, abstract = {

A data base of fire occurrence was established for the Gila Wilderness by analyzing fire scars and compiling fire records. Cross sections of 44 fire scarred ponderosa pine trees (Pinus ponderosa Laws.) were collected from three study areas. Crossdating of more than 800 individual fire scars revealed that extensive surface fires were a common occurrence prior to 1900. Mean fire intervals for a 250-year period prior to 1900 were approximately four to eight years and fire intervals ranged from one to 26 years. Intensive grazing and fire suppression efforts after 1900 resulted in a sudden decrease in number of fires recorded by the sample trees.

A 72-year record (1909-1980) of fire occurrence in the Gila National Forest was compiled from Forest Service records. The fire records and fire scar evidence suggest a need for continued emphasis on fuels reduction and greater flexibility in the Prescribed Natural Fire program.

}, keywords = {crossdate, dendrochronology, fire, fire history, fire scar, gila national forest, gila wilderness, new mexico, pinus ponderosa, ponderosa pine, tree ring}, author = {Swetnam, T.} }