Introduction to Laboratory and Staff

The Oxford Tree-Ring Laboratory was formed in 2010 by Michael Worthington and Jane Seiter to provide cutting-edge dendrochronological services to archaeologists, architectural historians, art historians, cultural resource managers, and private house owners. Dendrochronology, or tree-ring dating, is the science of dating wood utilizing the phenomenon of yearly tree-ring growth. By using this technique, we can provide precise calendar dates for wooden structures and other objects. Our latest project is a complete investigation and rethinking of the historical development of the Officers' Club at the Presidio in San Francisco, California. Our members of staff have dated buildings as diverse as Windsor Castle and Uncle Tom's Cabin (the Josiah Henson Site). Although we specialize in the tree-ring dating of standing buildings, we also provide dates for archaeological artifacts, boats, wooden panel paintings, and live trees. We accept private and commercial commissions throughout the USA, the UK, continental Europe, and the Caribbean and publish a comprehensive report for every commission that is undertaken.

Michael Worthington, Dendrochronologist

Michael Worthington is a dendrochronologist with extensive experience working on both sides of the Atlantic. Among the many buildings he has dated are Mount Vernon in Virginia; the birthplaces of John Adams and John Quincy Adams in Massachusetts; the Josiah Henson Site ("Uncle Tom's Cabin") in Maryland; Drayton Hall in South Carolina; the Officers’ Club at the Presidio in San Francisco, California; and Windsor Castle, Westminster Abbey, and the Tower of London in the U.K. He began his career in buildings as an industrial archaeologist at the Ironbridge Gorge Museum in Shropshire, England. After deciding to specialize in dendrochronology, he received his academic training at Oxford University through a grant from English Heritage. At Oxford he was a member of staff at the Research Laboratory for Archaeology and the History of Art and an assistant tutor on the master's degree course in Archaeological Science. As a co-founder and partner in the Oxford Dendrochronology Laboratory, he spent more than a decade building a series of base chronologies for historic buildings in America. Upon moving full-time to the United States in 2010, Michael opened the Oxford Tree-Ring Laboratory. He currently resides in Baltimore, Maryland..

Jane Seiter, Researcher and Archaeologist

Jane Seiter is a researcher and archaeologist working on a wide variety of historic sites both above and below ground in Europe, the Americas, and the Caribbean. She is a partner in the Oxford Tree-Ring Laboratory, where she records and researches the fabric of historic buildings, and has prepared numerous successful nominations to the National Register of Historic Places. She has more than twelve years of excavation experience on sites ranging from monasteries and Roman villas to colonial plantations and industrial complexes and has extensive experience in standing building recording, surveying, map regression, archival research, and the preparation of archaeological site reports, desktop surveys, and dendrochronological reports. Jane received a BA in American Studies from Yale University with magna cum laude honors and an MA in Landscape Archaeology from the University of Bristol. In July 2011 she completed her PhD at the University of Bristol with a dissertation analyzing material changes to the landscapes and settlements of the Caribbean during the 17th and 18th centuries. Before training as an archaeologist, Jane worked as an editor at Penguin Books in New York and as a private trust officer for Wells Fargo Bank in San Francisco. Jane currently resides in Baltimore, Maryland.




The Oxford Tree-Ring Laboratory provides cutting-edge commercial dendrochronological services to homeowners, architectural historians, and cultural resource managers. READ MORE

Contact Information

Oxford Tree-Ring Laboratory

Michael Worthington
Jane Seiter, Ph.D

25 E. Montgomery St.
Baltimore, MD 21230



Michael Worthington sampling a timber Drayton Hall SC

This is how we sample your building,  READ MORE

Basic Dendrochronology

The Laboratory's staff have been involved in scientific dating of over two hundred historic building both in the USA and UK. Detailed listing of all of them can be found READ MORE


Oldest building in  NC, Edenton

After two years of investigation of what was a planned rental property, the oldest dated house in North Carolina has been identified in Edenton.
Preservationists with the N.C. Historic Preservation Office, architectural historians with the Architectural Research Department at Colonial Williamsburg and local historians participated in the research. READ MORE

Book Shop

Front cover of the Chesapeake House book

Must Have Books!
For more than thirty years, the architectural research department at Colonial Williamsburg  READ MORE