Oxford Tree-Ring Laboratory - Massachusetts


Old Garrison House

Old Garrison House, Rockport, Essex County, Massachusetts (42.680978, -70.627003)

Felling Dates: Summer 1709, Spring 1711

This building is constructed principally of tamarack or eastern larch logs. However, the two boxed-heart chimney girts in the first floor ceiling are of slow-grown white oak, as well as the left-hand girt. All three timbers retained complete sapwood. The right-hand girt was also likely to be of oak, but this was concealed within and without, and the projecting end at the front jetty had been repaired, making sampling of this timber impossible without the removal of later finishes. The internal walls in the left-hand ground-floor room had later finished removed, exposing the logs. Trenched into the inside face of these logs are a series of diagonal braces. These looked to have excellent dendrochronological potential with good ring counts and sapwood. However, sampling was impossible due to the fact that they were set back into the trench, making it impossible to drill radially without causing visual damage to the braces. Upstairs windows were being replaced at the time of the assessment and sampling, revealing the cut ends of the logs internally. One log to the right front upstairs was inaccesible with out removing a significant amount of plaster, but in the left-hand bedroom, a small amount of plaster was removed to allow a core to be taken from a log to the left-hand end of the building.

In the attic, a few of the purlins were of oak, but these were boxed heart and relatively fast-grown, therefore were unsuitable for sampling. There were some timbers exposed in the cellar beneath the left-hand room. Although the main summer beam was of oak, it was covered in plastic, and as a result fairly damp, making successful sampling problematic. This timber also appeared to have a termite infestation.

Both upstairs and downstairs the walls were all of boxed-heart tamarack logs, except for a few exceptions mentioned above. Many of these retained complete under-bark edge. These logs are 7” thick and between 9” and 14” high. The chimney ties were also of tamarack. These timbers seemed to have between 50 and 100 rings and might make a worthwhile pilot study in comparing with western Massachusetts softwood chronologies.

Miles, D H, 2004 “The Tree-Ring Dating of the Old Castle, Pigeon Cove, and the Old Garrison House, 188 Granite Street, Rockport, Massachusetts”, ODL unpubl rep 2004/7




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Contact Information

Oxford Tree-Ring Laboratory

Michael Worthington
Jane Seiter, Ph.D

25 E. Montgomery St.
Baltimore, MD 21230