Growing the Eastern Hemlock Chronology of New York State
A Dendrochronological Report from the St. James AME Zion Church of Ithaca, NY
Sampling Protocols
Dendrochronology Field Kit Contents: archaeological dry-wood borer, drill, stabilizer, archival storage tube, masking tape, sharpie, saw, gloves
Sample collection of cores and sections in the Church bell tower and basement crawlspace. Ground penetrating radar (GPR) on the first floor of the Church (bottom right). Pictured: Dr. Brita Lorentzen, Jenna Martin, Prof. Sturt Manning, Olivia Graves, Mia Brown-Seguin, and Thomas Urban
Virtual Tour
St. James AME Zion Church Dendrochronology Tour
Lab Procedures
Sanding/polishing station
Microscope measuring platform with a crank to advance the sample and a plunger to record tree ring widths
Measurements populated in Tellervo (chronology software)
ISJC Data Analysis
During field sampling at the St. James AME Zion Church, dozens of cores and sections were collected, prepped, and measured. This report presents findings on subset of 12 ISJC (Ithaca St. James Church) samples that are all Eastern Hemlocks Tsuga canadensis. These 12 samples align with a long-term chronology of Eastern Hemlocks from the greater Central New York region. Raw data files were indexed: a process that helps to "clean" data to shrink the bias of exponential juvenile ring growth when visualizing a tree's lifetime. Indexed files were each assigned start and end dates after locating when on the overarching Eastern Hemlock chronology the sample and reference graphs best match.
What can we learn from this research?
This cohesive chronology links 12 different Eastern Hemlock samples collected from the interior of Ithaca's St. James AME Zion Church to match regional patterns of tree growth. This signifies a consistent state-wide response to variation in precipitation and temperature during the growing season.
Modeling the ISJC samples as a group alongside the overarching Eastern Hemlock chronology provides a high-resolution timeline of the church's construction and renovation events, quantitatively corroborating local records from the Church congregation's archives and knowledge. The data does not yet pinpoint the precise foundation date of the original building structure. However, the chronology records felling dates from 1620 to nearly 1900. In this period, the Hemlock timbers used would have been locally sourced and utilized shortly after felling, providing a timeline of the Church's construction and repairs. The individual t-values represent confidence in matches between ISJC samples against the regional Eastern Hemlock chronology, showing that the Church timbers align with data from the rest of Central New York.
The St. James AME Zion Church of Ithaca is one of many historic locations associated with the Underground Railroad in the Finger Lakes Region and is an ongoing excavation site for the Cornell Institute of Archaeology and Material Studies .
