There are about three trillion trees on Earth, and for researchers in the field of dendrochronology, they harbour invaluable information.
Dendrochronology concerns the study of annual growth rings in trees. It enables researchers to reconstruct what the climate has been like in different regions of the world many hundreds of years before modern measurements began. It is possible to trace events like a volcanic eruption at the beginning of the 19th century or when motorists in Cairo stopped driving cars with gasoline containing lead. Samples can be taken from both dead and living trees. If a tree is alive, a drill is used to carefully bore in towards the middle and extracts a sample. The tree then recovers from the procedure.
A picture says more than thousand words. Science Faculty Magazine takes a closer look at a scientific phenomenon.