Tree Ring Dating of the Ficklin-Imboden Log Structures, Powhatan Historic State Park, Arkansas

Powhatan Historic State Park in Powhatan, Arkansas preserves and interprets five historical structures from 19 century Arkansas, including the Ficklin-Imboden Log House. This structure, which is actually two separate log buildings with uncertain construction dates and functions, is believed to be the earliest surviving structure at Powhatan Historic State Park and is on the National Register of Historic Places. Powhatan Historic State Park contracted with the University of Arkansas Tree-Ring Laboratory to develop a more accurate dating and interpretation of the log structures. Dendrochronology (tree-ring dating) was used to determine the true felling dates of bald cypress (Taxodium distichum) logs in both buildings. Core specimens were extracted from 22 wall logs and 16 were dated with dendrochronology. The measured ring width data were used to develop a chronology for the buildings that was then correlated against other absolutely dated tree-ring chronologies from the region. The strong correlation among the ring width time series from both structures provided evidence that the trees from which the logs were cut grew contemporaneously in the same area. The derived mean ring width chronology is highly correlated with tree-ring reconstructions of the Palmer Drought Severity Index (PDSI) across Arkansas and the central US from 1726 to 1846 and with other regional tree-ring chronologies, particularly one created from living bald cypress trees at Allred Lake in southeast Missouri. All possible correlation analyses between the continuous FicklinImboden chronology and the Allred Lake chronology, advancing one year at a time over the past 808 years (1185–1992), indicate that the highest correlation (r = 0.45) is observed precisely where the log specimens were dated based on microscopic analysis and skeleton plot crossdating. The derived cutting dates extended from 1843 to 1846, with logs in both structures cut as late as 1846. Because the structures are in situ and the wall logs have not been extensively repaired or replaced, the cutting dates indicate that the structures were likely erected simultaneously during or soon after the growing season of 1846. This date is slightly earlier than the current interpretation by Powhatan Historic State Park, but still consistent with the documentary evidence that Andrew Imboden and his wife used the building as a home by 1851.