Two pine species from California which are famous for their longevity and have been used to develop an exceptionally long, arid-site, tree-ring chronology. The oldest living specimens date back more than 4600 years, but cross-dating these with remnants of dead bristlecone pines has extended the arid-site chronology to more than 8200 bp. A 5500-year chronology has been developed for bristlecone pines at the upper tree limit. These pines are also used to calibrate the radiocarbon-dating method to allow for fluctuations in atmospheric 14C:12C ratios as revealed by measuring the 14C:12C ratios of individual tree rings in the long, absolutely dated, tree-ring series. Pinus longaeva is the Great Basin bristlecone pine and P. aristata is the mountain bristlecone pine.
Subjects: Plant Sciences and Forestry — Ecology and Conservation.