Dendrochronology, that is.
John and I were a wee weary Monday morning, he after a weekend of roofing nana’s house and me running a goalie and a wingman to and fro hockey games. Then Michael showed up toting a small, specialized tool box and a wry smile.
The man had come to do some dendro on The Sagamore House.
Here’s a link to the ODL, The Oxford Dendrochronology Laboratory: http://www.oxford-dendrolab.com/basic_dendrochronology.asp They’ll do a far better job at explaining dendro. But suffice it to say, dendrochronology is the scientific method for establishing when the tree was alive and when it was felled, pretty much to the year, sometimes to the season. There’s a worldwide database with a myriad of examples in which to place the sample. Savvy scientists use microscopes and computers and, well, their savvy, to precisely date a sample. Anyone can count growth rings to reckon a tree’s age, but it takes dendrochronology to pinpoint when the tree was alive, and in turn, to give a precise date for the frame of a house. If the sample can be matched with a minimum number of spring-wood samples in the database, a date is born.
Michael told us of how archaeologists in Boston had discovered timber from mid-17th century mill before the infamous Big Dig got underway, and how the timber yielded a dendro sample revealing a tree which had been alive in the mid-15th century! Such an early example expands the database locally, and helps to fine tune the accuracy of the method.
Core samples are taken from the sapwood through the heartwood, ideally out to the other side. Multiple samples are best. The trick is finding timbers in an old frame which still have sapwood in them, which isn’t always easy. Often, sapwood’s been hewn or sawn away, or insects have left nothing but a powdery vapor.
But at Sagamore, we’ve been lucky to find a few framing timbers with intact sapwood, including the corner post on the east end of the house. The tool box was opened. Drilling would commence.
The specialized drill can turn very slowly but has plenty of torque.
Michael patiently works the drill into the post. Getting a proper sample takes time.
The core is carefully wrested from the bit…
And just like that–a core ready to be dated.
Interestingly, the cored piece bowed away on either end from the center almost immediately, just like you’d expect a newly sawn plank of green oak to do. Funny things happen when tension in the wood is released, he said, almost euphemistically.
The first sample was ok, but the sapwood was very fragile. Sometimes the separated sapwood can be glued back to the heartwood to make a complete core.
We will be sure to let you know the results of the dendro as soon as we find out.
Meanwhile, the house itself is coming along. The linseed oil-based red on the front of The Sagamore House really makes a statement. Personally, I really like what it has to say. Nice work C and K!
It’s good to see one face of the house on the cusp of being finished…
…even as we open up another–