Dendroarchaeology of the Salt Lake Tabernacle, Utah

We examined tree rings from Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) timbers in the Salt Lake Tabernacle, constructed from 1863–1867 in Salt Lake City, Utah. A seismic upgrade to the Tabernacle initiated in 2005 required the replacement of wooden timbers with steel beams. Our objectives were to 1) determine cutting dates for the timbers to identify logs that may have been salvaged from previous structures, and consequently would have greater historical significance, 2) identify the species and provenance of the timbers, and 3) develop a chronology that could extend or strengthen the existing tree-ring record for environmental and historical applications in northern Utah. We built a 162-year floating chronology from 13 cores and 15 cross-sections, crossdated visually using skeleton plots and verified statistically with COFECHA. Statistically significant (p , 0.0001) comparisons with established chronologies from northern Utah indicated that the Tabernacle chronology extends from 1702–1862. Cutting dates ranged from 1836–1863, with most in 1862 or 1863 and a smaller cluster around 1855. The broad range of cutting dates suggests that some of the timbers were used in previous structures, and that some trees were dead before they were cut. This study provides valuable information for the preservation of historical materials, and increases the sample depth of existing chronologies during the 18 and 19 Centuries.