@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}
}
@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 = {<p>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.</p>},
	keywords = {dendrochronology, fillmore canyon, fire, Geography, historical, new mexico, organ mountains, reconstruction},
	author = {Morino, Kiyomi Ann}
}
