Robert Karl and Dr. Matthew Bekker, Department of Geography

Pioneer history is a heritage of Utah. Utah was founded on the premise of pioneers venturing from the east and settling throughout Utah. Very few of these historic pioneer structures have been dated in the state of Utah and for many of these structures there exists only a rough idea of when they were built. Other structures have been dated but the information is unpublished and therefore unavailable to the general public and the scientific community. And, though the use of tree rings in archaeology has a rich history in the southwestern United States , most research has focused on Native American structures prior to the historical/pioneer era.

This project will provide many benefits with some listed below and others made by those that use the results from this project. 1) It will provide important and precise information for decisions regarding the preservation of historic structures. If historical information about a building is incorrect it can lead to the neglect or destruction of very significant structures, or to large amounts of money and time invested in less significant structures . 2) It will make completed but unpublished data on historic structures in Utah readily available to the general public and the scientific community through publication as primary literature. Tree-ring work on an individual structure is rarely published unless the building is of great public interest . 3) This project will include information from several structures, providing a bigger picture of pioneer migration, settlement, and construction practices. In addition, trees cut by the pioneers were often at the lowest elevations in mountain environments and those trees were the most sensitive to moisture, and thus will provide the best record of droughts. In some places almost all the trees were cut , so historic structures represent some of the best sources of old tree-ring records for other applications such as climate reconstructions.

Trees keep a record of their growth by producing annual rings in their stems and branches. The overall thickness or width of this annual ring is dependent on conditions surrounding the tree when that ring was formed, including moisture, temperature, soil nutrients, competition with other plants, and disturbances such as fires and insect outbreaks. Of these variables, climate (temperature and moisture) usually has the strongest and most consistent effect on annual growth over time (ex. Rings tend to be narrow in dry or cold years and wide in wet or warm years). Trees of the same or similar species that are growing in the same general environment will record a similar pattern of narrow and wide rings over time in response to variations in climate.

That said, for undated structures, tree-ring samples would be obtained by removing a small core with a hollow bit attached to a power drill (no harm done to the structure being sampled). Before sampling, each timber will be photographed and its location in the structure mapped and cataloged. Each sample will be inspected for the presence of bark or other indicators of an intact outer ring. The samples will then be mounted and sanded to a high polish to make the annual rings clearly visible. The samples will then be cross-dated with samples with known dates obtained from one of two sources: 1) established tree-ring records available through the International Tree-Ring Data Bank (http://www.ncdc.noaa.gov/paleo/treering.html); 2) samples from old, live trees of the same or similar species in the region where the building was constructed if no existing records are available through the ITRDB. Cross-dating will then be done using standard procedures , including visual analysis and statistical verification using the software COFECHA .

We obtained permission from Scott Christiansen to take samples of part of the house located in Salt Lake City (SLC). He purchased his home some 17 years ago and has since built onto it. It started as a little adobe 1 room house with a basement that was reportedly built in the mid to late 1850s. We took samples of the 15 logs located in the basement (basement being 3½ feet high). We sanded these samples until we could visibly see the cells of the tree rings. From these samples we have come to a preliminary construction date. Thus far four of our samples come with a cutting date of 1861 telling us that these logs would have been placed under the structure in 1861. Another interesting cluster of dates comes at about 1844 suggesting that these particular logs were used on a previous structure and then later used as part of the foundation of the structure being discussed. One hypothesis we have for this is that the house was built in two stages. The first stage (1840s), we suppose, may have been a mountain-man or trapper that built a small hut to live and store his hides and meat in while he resided there. Then, come 1861, the hut was added on to and made into a pioneer home.

We have also sampled a cabin in Pleasant Grove, Utah. This cabin was thought to be the oldest cabin in that city. When that article was published in the newspaper we Dendrochronologists found such a statement skeptical and asked the city officials if we could date it. After a little back and forth conversation we received permission to take some core samples and later found that the cabin was not as old as they originally thought. However, since the cabin was moved off of its foundation we desire to return and take some samples of the foundation logs perchance the foundation is actually as old as the city officials thought and the logs above the foundation had been placed at a later date.

We are also in contact with the caretakers of some unpublished data, which we hope to obtain. We will publish this data and add it to the tree-ring community so that both the scientific and public realms may access them.

One of the exciting things about this project, which I will enjoy in my work for years to come, is that I got to work with historic structures and was able to view the building methods of peoples past. I enjoyed working on this particular project and will continue working on it until it is completed in the next 5 months. Further research will be done on other historical structures in that time. This has been a good training ground for me and the research will prove beneficial to the general tree ring collections of both the scientific and public realms. This will be done through publishing our data and findings in journals accessible to both parties. I have also entered my research in the Mountain West Regional AAG conference and the Ira R. Fulton student poster conference at Brigham Young University in Provo, Utah.

References

• Nash, S. 1999. Time, Trees, and Prehistory: Tree-Ring Dating and the Development of North American Archaeology, 1914 – 1950. University of Utah Press, Salt Lake City. 294 pp.
• Grissino-Mayer, H.D. and Pitcaithley, D.T. 2005. Forensic Dendroarchaeology and the strange case of Abraham Lincoln’s Birthplace log cabin. Annual Meeting, Association of American Geographers, 5-9 April 2005, Denver, Colorado. Abstracts.
• Bekker, M.F. and Heath, D.M. 2007. Dendroarchaeology of the Salt Lake Tabernacle, Utah. Tree-Ring Research 63:95-104.
• Keller, C.L. 2001. The Lady in the Ore Bucket: A History of Settlement and Industry in the Tri-Canyon Area of the Wasatch Mountains. University of Utah Press, Salt Lake City.
• Stokes, M.A., and Smiley, T.L. 1968. An Introduction to Tree-Ring Dating. The University of Arizona Press: Tucson, Arizona.
• Grissino-Mayer, H.D. 2001. Evaluating crossdating accuracy: A manual and tutorial for the computer program COFECHA. Tree-Ring Research 5 7(2): 205–221.