"A Final Technical Report Submitted 31 May 1985 on the National Science Foundation grant EAR-8018687 for the period 1 April 1981 to 31 October 1984 with the assistance of the Department of Energy contract no. DE-AC02-81EV10680 covering the period 1 May 1981 to 31 October 1982" / Since Edmund Schulman’s initial interest in 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 east-central California where living trees reach ages in excess of 4,000 years. The focus of this report relates to the support by the Geology and Anthropology sections in the National Science Foundation under grant EAR-8018687 for the period 1 April 1981 to 31 October 1984 with the assistance of the Department of Energy contract no. DE-AC02-81EV10680 covering the period 1 May 1981 to 31 October 1982. A summary of this research was recently published in Radiocarbon (Ferguson and Graybill 1983). In most cases various facets of the work were related to projects sponsored by all agencies. Therefore the full range of activities during that period is described herein. The primary project goals were: To extend the bristlecone pine chronology from the White Mountains of California beyond 6700 B.C. and strengthen it by incorporating additional specimens. To develop bristlecone pine chronologies in new areas for applications in archaeology, isotopic studies, and other earth sciences. To furnish dendrochronologically dated wood to researchers engaged in the study of past variations in carbon isotopes and climate.

Understanding the impacts of climate change is critical for improving the conservation and management of ecosystems worldwide. Ecosystems vary along a precipitation and temperature gradient, ranging from tropical jungles to arid deserts. The Great Basin is a semi-arid eco-region that is found within the western United States. Plant communities within the Great Basin range from sagebrush valleys to sub-alpine conifer forests found at high elevation areas. It is predicted that the Great Basin will experience prolonged periods of drought, more intense fires, and greater variability in average annual and monthly precipitation, all in response to changes in climate patterns. At the lower elevations, sagebrush communities are expected to experience less suitable habitat conditions, however, less is understood about vegetation response at upper elevations. Understanding forest composition and structure at these upper elevations within the Great Basin will help us better understand potential impacts from climate change. In chapter 1, we characterized Pinus longaeva (Great Basin bristlecone pine D.K. Bailey) forest structure and composition. We mapped this tree species distribution and characterized forest structure and composition using a sampling protocol that included both biophysical variables and individual tree characteristics. We collected data from 69 mixed and homogenous P. longaeva stands found within the Great Basin and Colorado Plateau. Results suggest that P. longaeva forest structure and composition exhibit high structural variability in tree characteristic measurements like density, basal area, growth rate, age, and in biophysical variables such as substrate type, slope, aspect, elevation, average monthly temperature and precipitation, latitude, and longitude. This study also found that variability in forest composition and structure in P. longaeva forests allows for greater flexibility in the breadth of life-history strategies and probable resiliency to climate change. In chapter 2 we used remote sensing images with high spatial resolution to identify 685 unique P. longaeva stands on 42 mountain ranges. Pinus longaeva was found on the White Mountains on the western edge of the Great Basin to the Colorado Plateau's Henry Mountain and West Tavaputs Plateau in the East, and from the Spring Mountains in the South to the Ruby and Spruce Mountains in the North. Stands covered 113,886 ha across the geographic distribution. A comparison between our maps and those produced by David Charlet found a total of 36% overlap of P. longaeva. We mapped 58 unique stands that the control dataset lacked and 11 stands that we did not include. We believe that this is the most comprehensive P. longaeva distribution map created to date.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The development of tree-ring chronology for bristlecone pine (Pinus aristata), stretching over 8,200 years, has been used to calibrate the radiocarbon time scale. An extensive deposit of driftwood in Stanton's cave in the grand canyon was estimated to have been deposited on the cave floor about 12,000 years ago on the basis of the 4,095-year radiocarbon age of a split-twig figurine on the surface of the cave floor. However, the initial driftwood specimen gave the surprising C-14 age of 35,000 years. A tree-ring dating study was therefore undertaken on driftwood in the grand canyon in order to: (1) evaluate the driftwood deposit in Stanton's cave; (2) provide a basis for interpreting c-14 dates from canyon archaeological sites; and (3) document a technique for deriving some concept of pre-dam hydrology, especially maximum high water levels. The percentage of dated specimens found indicated that the approach was feasible. A likely interpretation of the seemingly early c-14 dates at archaeological sites is that prehistoric man used old driftwood, as does modern man in the canyon. Tree-ring dates from wood above the pre-dam high water mark indicate that maximum 100-year flood evidence can be obtained.