Wouldn’t the test show how old the tree was from which the canoe was carved, not when the carving was done? Or am I missing something?
It would show when the tree tissue last lived.
Right, the RC dating shows the oldest possible date, which is the youngest ring; if the bark is present (possible, but unlikely), the date of the cutting can be found. But this is a hollowed out log; the only missing layer is likely to be the last one, so, they know when it was cut. :’)
Generally people build things out of freshly cut wood. They might have even taken advantage of a fallen log that was one or two years old, but after that the logs tend to rot. So the reasonable assumption is that this was carved within a short time frame of when the tree died.