Wood Conservation at the Gray Fossil Site in Northeastern Tennessee

• Main Authors: Madsen, Owen, Widga, Chris
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2020
• Subjects: Gray Fossil Site; Paleontology; Fossil Wood; Other Nat Resources and Ag and Env Sciences
• Online Access: https://dc.etsu.edu/asrf/2020/presentations/7; https://dc.etsu.edu/cgi/viewcontent.cgi?article=1492&context=asrf

The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. When excavated, the wood is saturated due to a modern local high water table. Moisture in the wood prevents further dendroecological research, which would provide important, annual-scale climate information from tree rings visible in the wood. In order to analyze climate-sensitive wood variables, wood samples must be dried with minimal cracking prior to further research. To test the best method for drying wood samples, a variety of methods were studied. Cotton string, wrapped firmly around a sample, and a sandbox, comprised of a sample surrounded equally on all sides by sand within a five gallon container, were both be used to test the effects of minimizing expansion and contraction during drying. A vacuum oven, a microwave, and a refrigerator were used to monitor the rate at which the wood dries under different temperature conditions, and a control sample was dried in a fume hood as a comparison. An alcohol replacement test provided data on the rate of non-water evaporation. Drying methods were evaluated by measuring the drying speed of each sample and the degree of visible surface cracking. Of the methods tested, wrapping wood samples in cotton string at an even pressure, then allowing the sample to dry in a fume hood is the best practice for drying the wood from the Gray Fossil Site. The string resulted in the least cracking, and one of the shorter drying times without destroying the sample, as the vacuum oven and microwave tests did. This work not only provides a comparison of standard drying methods for saturated fossils of the non-wood varieties, but lays the groundwork for further studies examining the wood, tree rings, and climate at the Gray Fossil Site.