Analysis of Radial Growth Patterns of Strip-Bark and Whole-Bark Bristlecone Pine Trees in the White Mountains of California: Implications in Paleoclimatology and Archaeology of the Great Basin

摘要

Dendrochronology focuses on the relationship between a tree's growth and its environment and thus investigates interdisciplinary questions related to archaeology, climate, ecology, and global climate change. In this study, I examine the growth of two forms of bristlecone pine (Pinus longaeva): strip-bark and whole-bark trees from two subalpine adjacent sites: Patriarch Grove and Sheep Mountain in the White Mountains of California. Classical tree-ring width analysis is utilized to test a hypothesis related to a proposed effect of the strip-bark formation on trees' utilization of atmospheric carbon dioxide. This effect has grown to be controversial because of the dual effect of temperature and carbon dioxide on trees' growth. The proposed effect is hypothesized to have accelerated growth since 1850 that produced wider rings, and the relation of the latter topic to anthropogenic activities and climate change. An interdisciplinary approach is taken by answering a question that relates temperature inferences and precipitation reconstructions from the chronologies developed in the study and other chronologies to Native Americans subsistence settlements and alpine villages in the White Mountains. Strip-bark trees do exhibit an enhanced growth that varies between sites. Strip-bark trees grow faster than whole-bark trees, however, accelerated growth is also evident in whole-bark trees but to a lesser degree. No evidence can be provided on the cause of the accelerated growth from the methods used. In the archaeological study, 88% of the calibrated radiocarbon dates from the alpine villages of the White Mountains cluster around above average precipitation, while no straightforward relationship can be established with temperature variations. These results confirm that water is the essence of life in the desert.