You'll start with a tree-ring sample from a living tree and, using other samples, piece together a pattern of rings that stretches back through time.

The researchers analyzed genomic variation from more than 1,000 individual trees from 61 separate populations around the Oregon ash range. Some of the samples are shown here. Credit must be given ...

For the study, scientists collected wood samples from red cedar trees in Australia, Thailand, and Bangladesh using a hollow drill. This drill extracts a cylindrical piece of wood from the tree ...