Melanie Cooke, University of Utah
Geography
Range Creek is a small deeply incised canyon located in south central Utah. It is a remote canyon that has experienced minimal impact to its rich archaeological heritage by European-American settlers during the last two hundred years. The canyon contains hundreds of important archaeological sites and thousands of artifacts from the Fremont culture that inhabited the area from around 800 A.D. to 1350 A.D. Though work has been done on the archeological sites in the canyon, a better understanding of the paleoclimate and environment are needed to help understand why the Fremont culture disappeared so abruptly around 1160 A.D.Dendrochronology has been shown to provide excellent data for reconstruction of climatic conditions. Conifer tree species, including Douglas fir (Pseudotsuga mensiezii), are well-suited for studying past climate through the analysis of their tree rings. In this study, I use increment cores from Douglas fir to build a local history of tree-ring growth rates through time and will compare these results to regionally available climate records. By comparing changes in ring widths with weather station data, including monthly and seasonal temperature and precipitation records, I hypothesize that Douglas fir will provide a sensitive indicator of past changes in winter precipitation. Twelve tree cores collected from climatically sensitive locations during the 2012 summer are being analyzed from Range Creek Canyon. Preliminary analyses of the tree ring series suggests this study will provide a climatic history spanning the past ~300 years. Although this analysis cannot provide direct observation on climate conditions during the period of the Freemont occupation and abandonment of Range Creek, it will provide insights into the natural climate variability occurring within the Range Creek Canyon. All tree cores are being analyzed with ARSTAN and COFECHA software, commonly used by dendrochronologists, and results will be made available at the time of presentation.