Up on Mt Rainier in Washington there's some exceptional tree growth. Dating to the year 1290 and cut down in 1963, this cross-section of the Longmire Tree is labeled along its rings with significant historical dates and a record of environmental events such as the eruption of Mount St. Helens. By examining the growth rings of a tree, dendroclimatologists can discern a picture of Earth’s temperature over a period of time. The larger the tree, the farther back in time you can peek.

07.19.17