By Audrey Cross
A tree corer used to drill into a trunk, and two tree cores. Rings are counted from these cores and used to date events or reconstruct climate change. Wikimedia Commons.
In dendrochronology, most analyses rely on a number of underlying assumptions. For wood that was used by humans, a tree might have been used immediately after it died, and it could be found at a site nearby where the tree had lived. However, humans could obtain wood in different ways; it could be found, as with driftwood; recycled, as with beams in houses; or transported, as with boats.
The study of driftwood proposes an interesting twist to dendrochronological analysis because the amount of time that wood can spend in transport can vary greatly. Continue reading
By Erin Hayes-Pontius
To add to the seemingly never-ending list of proxies paleoecologists use to study the past, here’s another one: trees. If you have been following this blog for a little while, you probably read about what pollen can tell us, but using the trees themselves, rather than their pollen, can tell an entirely different story. Studying the pollen that accumulates in lake sediments has the distinct advantage of providing a record that is as old as the lake itself, which can sometimes be up to millions of years old. However, because of how long it takes lake sediments to accumulate, we cannot always be very confident of the date a particular layer of sediment represents. In contrast, trees generally provide a much shorter record than pollen, but because of their annual rings, give us an annual record to work with.
A device used to extract thin cores from trees (Wikimedia Commons: Beentree 2006).