@mastersthesis {511, title = {Unraveling environmental factors that affect Pinus longaeva growth in the White Mountains, California}, volume = {PhD}, year = {2010}, school = {University of Arizona}, abstract = {

Two of the most pressing questions involving ancient bristlecone pines are how microsite factors lead to differences in tree responses to climate at high-elevation sites, and how global change has impacted growing season events. Disparities in climate response at treeline and subalpine locations have been associated with local environmental characteristics while the increasing growth trend found at treeline has been linked to warming. In this study, environmental conditions were considered in order to identify microsite differences between trees growing at two different elevations on four aspects of a conical-shaped mountain in the White Mountains, California. Dendrochronological, environmental, correlational, and spectral methods were employed to explore differences in ring-width chronologies. Albedo, soil thickness, and percent slope led to ring-width variability. Northwestern upper site was most highly correlated with precipitation, while the Southeastern lower site showed a strong negative correlation with temperature. This work indicates that selection of climate-sensitive trees a priori necessitates the consideration of local environmental factors, and these microsite differences resulted in different climate responses between nearby trees. By monitoring growing season events at the historic phenology site from the 1962-64 (Fritts 1969), natural variations and responses to climate change can be identified. Morphological and physiological phenophases, dendrometer traces, and environmental data were collected throughout the summers of 2007 and 2008. Duration and timing of cambial activity (tracheid lifespan) in the present study were similar to those recorded in the Fritts (1969) investigation, while pollination onset and bud opening occurred earlier in this study. No change was found in duration and timing of cambial activity suggesting that changes in cambial phenology are not an explanation for the increasing growth trend found at upper forest borders. On the other hand, changes in bud opening and pollination onset may be related to recent warming. To monitor diurnal and seasonal stem variability as part of phenologic studies on several trees, a point potentiometer dendrometer was designed. The newly designed point potentiometer dendrometer was tested in multiple environments and found to be versatile, cost-effective, and portable, working well in semi-arid and arid environments.

}, keywords = {Physical geography}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=2108905281\&sid=32\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Hallman, Christine Lee} } @mastersthesis {539, title = {Using False Rings to Reconstruct Local Drought Severity Patterns on a Semiarid River}, volume = {PhD}, year = {2008}, school = {University of Arizona}, abstract = {In this research, I describe the use of false rings to reconstruct local histories of seasonal drought in riparian ecosystems in semiarid regions. In tree-ring analysis, false rings are boundary-like features often formed as a response to drought within the growing season. Drought can be a common feature in hydrologic regimes of dryland rivers but in recent decades drought has been intensifying due to climate change and increasing water use by cities, agriculture and industry. Identifying when and where water availability has decreased along the river course is critical for understanding, and therefore managing, these generally endangered ecosystems. The higher density of trees compared to instrumental data make them ideal candidates for reconstructing site-specific drought patterns. The first part of this dissertation is an observational study conducted on the San Pedro River in southeastern Arizona during 2002. I used dendrometer data and local hydrological data to show that a period of negligible radial growth in cottonwood during the middle of the growing season coincided with a channel drying event. Tree-ring core samples confirmed that false-rings had formed in each of the instrumented trees. The second part of this dissertation is an experimental study designed to evaluate the effect of different levels of water stress on false-ring formation in cottonwood and willow. I showed that experimental decreases in water availability for periods as short as ten days were enough to induce false-ring formation in willow. Longer periods of reduced water availability were generally required to induce false-ring formation in cottonwood. In the final part of this dissertation, I reconstructed false-ring occurrence in Fremont cottonwoods at three sites along the San Pedro River. I infer from false-ring frequencies that the severity of summer drought has been increasing over the last four to six decades but that the drought severity varies along a hydrological gradient. Overall, the findings in this body of research confirm that false rings in riparian tree species can be used as indicators of seasonal drought and underscore the importance of identifying site-specific responses to reduced water availability along the riparian corridor.}, keywords = {Geography}, url = {http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=1500068401\&sid=3\&Fmt=2\&clientId=43922\&RQT=309\&VName=PQD}, author = {Morino, Kiyomi Ann} } @proceedings {750, title = {The Use and Limitation of Dendrochronology in Studying the Effects of Air Pollution on Forests}, year = {1985}, note = {

Copies of this are available in the Tree Ring Laboratory. Please contact the curator for more information. pcreasman@ltrr.arizona.edu

}, keywords = {agriculture, air pollution, climate, dendrochronology, environment, forests, wetlands}, author = {Cook, Edward Roger} } @mastersthesis {534, title = {{\"U}ber den Witterungseinflu{\ss} auf die Jahrringstruktur der Gemeinen Keifer (Pinus silvestris L.)}, volume = {PhD}, year = {1984}, school = {University of Freiburg}, author = {Merkel, Hubert} } @article {924, title = {Unsolicited Proposal Submitted to the Department of Energy for Dendrochronology of Bristlecone Pine}, year = {1980}, month = {04/1980}, institution = {Laboratory of Tree-Ring Research}, address = {Tucson}, abstract = {

Since 1953 the Laboratory of Tree-Ring Research has conducted dendrochronological studies of bristlecone pine (Pinus longaeva D. K. Bailey, sp. nov.) in the White Mountains of California. This research resulted in the establishment of a continuous tree-ring sequence of 8,680 years which proved to be a unique source of chronological data and provided precisely dated wood specimens essential to certain paleoenvironmental and geophysical investigations. Dendrochronologically dated decade samples of bristlecone pine continue to be supplied to C-14 laboratories for the calibration of the radiocarbon time scale, a development of far reaching consequences in the fields of archaeology and geology. To more fully understand the causative factors, especially the activity of the sun, a critical need exists to better define the fluctuations and trends of the C-14 curve through even stronger and earlier bristlecone pine controls. In addition, recent advances in other methods of analyzing past climatic variability \–particularly techniques involving stable isotope ratios\—have greatly increased the demand for wood of known age and, hence, for chronology development.

During the past 18 months, the early portions of the chronology have been greatly strengthened and extended. The objective of the proposed research is to continue the extension of the bristlecone pine chronology further into the past and to strengthen it by incorporating additional dated specimens from the White Mountains and nearby areas. Prospects for a 10,000-year chronology appear increasingly possible.

}, keywords = {Bristlecone, bristlecone pine, C-14, california, chronology, dendrochronology, department of energy, pinus longaeva, radiocarbon, white mountains}, author = {Ferguson, C.W.} } @article {718, title = {University of Arizona Eclipse Expedition}, volume = {XXXI}, year = {1923}, keywords = {astronomy, Douglass, eclipse expedition, university of arizona}, author = {Douglass, A.E.} } @article {719, title = {University of Arizona Eclipse Expedition, Port Libertad, Sonora, Mexico}, journal = {Publications of the Astronomical Society of the Pacific}, volume = {XXXVI}, year = {1923}, keywords = {astronomy, Douglass, eclipse, expedition, Mexico, port libertad, Sonora, university of arizona}, author = {Douglass, A.E.} }