Oldest Living Tree in the World

The world's oldest known living tree, a conifer that first took root at the end of the last Ice Age, has been discovered in Sweden, researchers say.

The visible portion of the 13-foot-tall (4-meter-tall) "Christmas tree" isn't ancient, but its root system has been growing for 9,550 years, according to a team led by Leif Kullman, professor at Umeå University's department of ecology and environmental science in Sweden.

Discovered in 2004, the lone Norway spruce—of the species traditionally used to decorate European homes during Christmas—represents the planet's longest-lived identified plant, Kullman said.

The researchers found the shrubby mountain survivor at an altitude of 2,985 feet (910 meters) in Dalarna Province. The tree's incredible longevity is largely due to its ability to clone itself, Kullman said. The spruce's stems or trunks have a lifespan of around 600 years, "but as soon as a stem dies, a new one emerges from the same root stock," Kullman explained. "So the tree has a very long life expectancy."

Radiocarbon Dating

Bristlecone pines in the western United States are generally recognized as the world's oldest continuously standing trees. The most ancient recorded, from California's White Mountains, is dated to around 5,000 years ago. Bristlecone pines are aged by counting tree rings, which form annually within their trunks. But in the case of the Norway spruce, ancient remnants of its roots were radiocarbon dated. The study team also identified other ancient spruces in Sweden that were between 5,000 and 6,000 years old. [source: National Geo]