Authors: Maegen Rochner*, University of Louisville, Matthew Bekker, Brigham Young University , Sally Horn, University of Tennessee
Topics: Paleoenvironmental Change
Keywords: dendrochronology, frost rings, volcanic history, whitebark pine
Session Type: Paper
Presentation File: No File Uploaded
Explosive volcanic eruptions are a well-known cause of natural climate variability, but local and regional proxy records are needed to identify the spatial extent of past volcanic influences on surface temperatures. Tree-ring characteristics including frost rings, tree ring minima, and maximum latewood density have been used to examine temporal associations between volcanic eruptions and tree-ring records and to thereby infer the influences of volcanic forcing at a variety of scales. For this study, we investigated the potential of two millennial-length tree-ring chronologies to record volcanic cooling events in the Beartooth Mountains of northwest Wyoming. We combined frost-ring years, tree-ring minima, and periods of suppressed growth in our chronologies with climate records and ice core and tree-ring proxy data to identify times when multiple lines of evidence support volcanic cooling in our study region. We identified tree-ring evidence indicating cooling in response to five volcanic events and longer periods of activity, including the eruptions of Huaynaputina, Peru in 1600 CE, Parker, Philippines and others in 1640/1641 CE, Tambora, Indonesia in 1815 CE, Cosigüina, Nicaragua in 1835 CE, Agung, Bali in 1963–1964 CE, and other potential volcanic events during the early nineteenth century that contributed, along with solar forcing, to cooler than average conditions across the western U.S. The combination of tree-ring evidence with ice core signals and other tree-ring studies highlights the ability of tree rings in the Beartooth Mountains to record volcanic events and to thereby provide more information about the spatial extent of past volcanic influences.