Tree-ring analysis determines Stewart Cabin is more than 200 years old
By DARRIN RUBINO and CHRIS BAAS
Most of us have counted the tree rings on a stump to determine how old a tree was when it was cut. We use tree rings for a much different purpose. We are Darrin Rubino, a biology professor at Hanover College (Hanover, Indiana) and Chris Baas, an associate professor of landscape architecture at Ball State University (Muncie, Indiana).
For more than a decade we, along with many undergraduate students from Hanover College and graduate students from Ball State, have been using tree rings to date the construction of historical buildings. We have worked on more than 200 buildings (houses, churches, mills, barns, smokehouses, etc.) throughout the Ohio River Valley.
To date a structure using tree rings, we normally use a borer and extract a cylinder of wood about the width of permanent marker. In the lab, we mount the sample and sand the wood using a 10-step process so that we create a smooth surface that allows us to identify individual tree rings. Plots of the individual ring widths are made, and each ring is then measured to the nearest 0.01 mm (0.0004 inches) under a microscope. Next, we note the pattern of growth in the wood. Tree-ring width varies from year to year with larger rings being produced in years of favorable growth conditions and smaller rings (sometimes no ring at all) in stressful years such as droughts. The trees, therefore, record this climatic signal, along with any other factors that impact growth, in their annual rings.
To determine the actual year a tree ring was formed, we use a process called cross dating. Cross dating has proven to be a very useful tool for determining the age of wood throughout the United States and Europe. We cross date samples by matching the pattern of small and large years in undated samples to samples that have been accurately dated (living trees, for example). In essence, we try to “read” the trees’ story and interpret it by comparing growth among many other trees from throughout the region. Regionally, we have reliable growth patterns that we consistently find. For example, we normally find small rings in 1737, 1770, 1774, 1779, 1803, 1816, 1834, and 1839. We try to find these “marker years” when we date a piece of wood.
Recently, we had the great fortune and pleasure to determine the construction date of the Stewart Cabin. This interesting log structure was discovered inside a larger house when it was dismantled in Stanford, Kentucky. The Logan-Whitley Chapter DAR via member Lynda Closson, and with permission from owner Ms. Regina Williams, invited us to sample some of the timbers that had inadvertently been removed form a wall of the old cabin during demolition. We sampled tulip poplar, ash, and buckeye timbers; given the condition of the timbers, we could not core them and chose instead to take sections using a chain saw. We prepared the samples and cross dated them with regional tree-ring samples with known dates. From these timbers we were able to create a tree-ring series that spanned from 1639 to 1811; we were able to date 1544 tree rings from nine different timbers. All of the wall timbers had a cutting or harvest date of 1811. We can conclude that the structure was most likely built after July of 1811 and before April of 1812 (in April, a tree begins to form its new tree ring).
We are always on the hunt for new historical buildings to analyze. The information in their timber is a treasure trove. The timbers’ tree rings not only allow us to determine a construction date for a building, but they also can be used to interpret how climate (droughts) or storms (ice storms or tornadoes) affected our forests. Also, cultural history is locked in old buildings. By examining them, we can better understand how people interacted with their forests and changed the landscape over time. Each building we analyze gives us more information about the past. As we lose more and more of these structures to time, valuable history is lost forever. We are currently working on several other buildings in Lincoln County and hope to uncover more of the rich history of the region.
Anyone who would like to donate to this denrochronlogy study project of historic buildings in Lincoln, Garrard, Boyle and other surrounding counties may send their check made payable to Logan-Whitley Chapter, DAR and mail it to Lynda Closson, P. O. Box 236, Danville, KY 40423.
If you have an historic building that you would like included in this study please contact Closson at 606-365-1776 or you can email LoganWhitleyChapter@gmail.com
Dr. Darrin Rubino can be reached at email@example.com and Chris Baas can be reached at firstname.lastname@example.org. If you’d like to learn more about dating historic buildings check out the newly released book by Rubino and Baas “Dating Buildings and Landscapes with Tree-Ring Analysis: An Introduction with Case Studies.”
BY ZAC OAKES email@example.com Charles Booker has come a long way, from growing up in an economically disadvantaged neighborhood in... read more