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Dendrochronology of Bristlecone PineSince 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.
Reconstruction of Past Climatic Variability: Final Technical ReportResults are reported from the first three years of a five-year project to reconstruct past climatic fluctuations in the Northern Hemisphere from variations in the growth rings of trees. The most significant result is the growing international collaboration stimulated by this research effort. The second is the development of 127 high-quality tree-ring chronologies from North America and Europe. Other developments include the establishment of the International Tree-Ring Data Bank, evaluation of multivariate techniques for calibration and analysis, the selection of a revised data set for reconstructing North American climate, and several other technical achievements. These results now will be used to improve reconstructions of past climate and to expand them to eastern North America and Europe.