Yesterday I wrote that I thought Frederick Forsyth had made a humorous gaff -- claiming that one could date a painting on panel by counting the grain lines on that panel. It struck me as funny. How could one know when the panel was cut just by counting the grain/rings of the tree it was cut from? At the most (it seemed to me) one might be able to conclude how old the tree was when it was cut down -- but not WHEN it was cut down.
I was wrong.
What Mr Forsyth did not mention in the narrative, but I found out in my subsequent research...
One can date Northern European oak -- meaning: One can tell when the tree grew and was cut down, not so much by counting the grain/rings, but rather, by observing the grain rings.
See, what I didn't know, and Mr Forsyth didn't include in his narrative, is that all oaks that grow in the same climate/weather conditions, will have similar size and order of size to their growth rings. Because weather patterns of (for example)one dry year followed by one wet year will show up in the size of the growth rings of those consecutive years in all the oaks of the region, the patterns will be the same in all the oaks of the region. Therefore, one can tell the period of time in which that tree grew -- not just how old it was when cut.
Further, what I found out is that these patterns of growth rings in European oaks have been catalogued for this very use. The other side of that coin is that because of those growth rings, we also know the relative weather of a given year in Northern Europe because we know how fat or skinny that year's ring is.
Pretty cool, really.
Incidentally, there is a sort of correlary in the clay world. Maybe I'll post about that tomorrow.