This Swedish Spruce is the world's oldest living tree. The stem you can see in the picture is 13 foot tall and less than 600 years old, but what interests us is what's underground.

Professor Leif Kullman of Umeå University explains, "as soon as a stem dies, a new one emerges from the same root stock, so the tree has a very long life expectancy."

Recent radio carbon dating at a lab in Miami found three generations of wood amongst the roots system dating back 375 years, 5,660 years and a staggering 9,500 years old. What's more all generations share the same genetic sequence, meaning this tree originally germinated just after the last ice age.

Photograph by Leif Kullman of Umeå University's Department of Ecology and Environmental Science