Using Charcoal to Investigate Prehistoric Trees

When charcoal is recovered from archaeological digs, experts can use microscopes to examine the structure of the charcoal and deduce what species of tree it's from. This can provide information about the spread of trees, and at a dig in Assynt in the Highlands of Scotland it's been used to reveal that the area used to have a much more diverse collection of trees than we'd suspected. The BBC has more details, but basically archaeologists working on a "crescent shaped mound of stones" found a metre deep pit filled with charcoal that connected to a stream. The purpose of the pit is uncertain, but was possibly a bathing pool or a "sauna" type structure.