Geology of the Las Vegas area
We document a rich Upper Triassic bonebed in Borden County, Texas in either the uppermost Tecovas Formation or, more likely, the Trujillo Formation of the Chinle Group, that represents one of the highest stratigraphic occurrences of the aberrant archosauromorph reptile Trilophosaurus. The associated fauna includes indeterminate coprolites, unionid bivalves, osteichthyans, indeterminate reptiles, a possible ornithischian dinosaur, and the putative theropod dinosaur Spinosuchus caseanus Huene.
Interacting Effects of Fire Activity, Climate, and Habitat Diversity on Forest Dynamics, El Malpais National Monument, New Mexico, USA
iii ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Henri Grissino-Mayer, for his guidance and mentorship through my master's career. Henri's help in the field, in the laboratory, and in the classroom was essential to the production of this thesis. I would also like to show great gratitude for my committee members, Drs. Sally Horn and Philip Li, for their words of wisdom, inside of the classroom and in the process of forming and conducting my thesis project. I must thank the National Park Service for funding the field work conducted in June of 2011, as well as the staff of El Malpais National Monument for their support and aid through the implementation of the project. I owe a large debt of gratitude to my field team, which consisted of fellow lab members: Grant and Dave Dukart of El Malpais National Monument. Without them, it would have been impossible to collect over 700 cores in only a week's time. I am eternally grateful to my friends and colleagues in the Laboratory of Tree-invaluable source of help during the months of processing cores, and my labmates provided much needed thoughtful discussion and camaraderie while I was forming my research questions and focusing my project. I would lastly like to thank my external sources of support: my family and best friends, who have been a constant source of encouragement, support, and relief. iv ABSTRACT The historic effects of fire and climate on stand dynamics in the ponderosa pine-dominated forests of the American Southwest are of increasing concern to land management agencies. Using present forest stand structure, the mixed-conifer forests of the volcanic features in El Malpais National Monument were analyzed at three separate sites: a cinder cone, an ancient basalt flow, and an isolated " island " (kipuka) completely surrounded by basalt flows. Increment cores were collected from 632 trees in 19 plots within the monument to obtain dates of establishment. These dates were compared with historic fire histories and precipitation records to analyze the effects of both fire and climate-forcing mechanisms on establishment of several tree species within each forest. Results show an increase in tree establishment that coincides with increased precipitation in the 1800s. Fire regimes were also altered, shifting from a predominance of small, patchy fires to that of larger, more widespread fires. Over the past 350 years, rates of tree establishment have responded positively to increased precipitation …
Remotely-Piloted Helicopter Citrus Yield Map Estimation
A remotely-piloted Gas Xcell mini-helicopter with GPS, wireless Ethernet, and a machinevision system was flown over orange trees to take overhead images. The individual tree images were processed to estimate the number of orange pixels in the images. The fruit yield of individualtrees at harvest a month later had an r-squared value of 0.373 with the number of orange pixels onthe irrigated tree images. While it was demonstrated that a remotely-piloted mini-helicopter could beused to acquire useful overhead images of citrus trees, substantial further research is needed toimprove the accuracy of estimates of individual tree yields or health.