Wood is dated in part by matching it to known samples from other trees from southern New England.
Definitively dating an old house can be tricky. Today, we have things like photographs and land records, but how would you figure out a house's age without that kind of stuff?
"We know that George Hyland, for whom the house is named, moved to Guilford in 1657 and we know he bought the property around that time," said Grace Zimmer, with the Hyland House Museum, a house on the National Register of Historic Places in Guilford. "But it was never clear when the house that exists on the site was actually built."
Zimmer said they turned to the science of dendrochronology. Archeologists from the Oxford Dendrochronology Laboratory took long core samples from the wood used to frame the house. That wood was shipped back to a lab and analyzed under a microscope to precisely study their rings.
"We all know that you can look and a tree will grow a new ring each year," Zimmer said. "By comparing the relative size of each ring and matching it to known samples from other trees from southern New England, they were able to say that the main trees that formed the framing of the Hyland House started growing in the late 15th century, and were cut down in 1712, 1713."
Historical records indicate builders in the early 18th century typically used felled wood immediately after harvesting it, so it's believed the sampled oak trees were used to construct the house that same year.
"We're kind of proud that our house now becomes an anchoring point for other researchers," Zimmer said. "Because now that we know it was definitively built in 1713, they can compare other structures whose dates are more uncertain and try to estimate those houses' dates."
Here's one more interesting fact: Zimmer said the analysis determined that trees used to frame the house would have been growing before Christopher Columbus arrived in the New World in 1492.