The world's oldest tree has been found on a mountain in central Sweden – and it is still growing. The 9,500-year-old Norwegian Spruce was discovered by scientists at Umeå University during a 2004 tree census in Fulufjällets National Park in Sweden. The age of the tree was established using carbon-14 dating at a laboratory in Miami, Florida after an investigation by the university. Growing old: The 9,500-year-old Norwegian Spruce is believed to be the world's oldest tree, and grows on a mountain in central Sweden.

The tree, named Old Tjikko, pictured on a less cold day, was found by a team of scientists during a 2004 census. It has been able to survive so long thanks to the process of vegetative propagation, which means it is able to effectively clone itself. While the visible portion of the 13ft tall tree is relatively new, its root system has been growing for almost ten thousand years. The parts of the root system that were sent to the United States dated back nearly 10,000 years, it is possible that other parts are older, locals told Aftonbladet.

Cold and old: The tree's age was established by a laboratory in Florida which analysed parts of the root system. Spruced up: The trunk and firs are significantly younger than 9,500 years, but the root system has been growing underground since the last ice age. 'During the ice age sea level was 120 meters lower than today and much of what is now the North Sea in the waters between England and Norway was at that time forest,' Professor Leif Kullman, professor of Physical Geography at Umeå University, said. 'I can imagine that it may be probable that the first firs came from these areas.' Professor Kullman has named the tree Old Tjikko, after his Siberian Husky. He says wind and low temperature have seen the tree end up 'like a bonsai tree' with a lot of firs and a small trunk. 'Big trees cannot get as old as this,' he told Aftonbladet.

Old Tjikko's Staggeringly Long Life. According to carbon dating, Old Tjikko sprouted around 7550 BC, making it older than written history. It is the world's oldest known Norway Spruce, and spent the first few thousand years of its life as a shrub formation known as a krummholz. Kullman stated that "the fact that we can see this spruce as a tree today is a consequence of recent climate warming since about 1915." The area the tree first sprouted in almost 10,000 years ago was a harsh tundra region, but, as the climate began to warm, the tree was able to grow from a shrub to a normal tree formation. The discovery of a tree that old in the region also proved that the climate in Sweden had actually warmed much earlier than scientist had previously believed, allowing Old Tjikko and other ancient Norway Spruces to grow in the surrounding area.

The tree has survived for so long due to vegetative cloning. The visible tree is relatively young, but it is part of an older root system which dates back thousands of years. The trunk of the tree may die and regrow multiple times, but the tree's root system remains intact and in turn sprouts another trunk. The trunk may only live for about 600 years, and when one trunk dies another eventually grows back in its place. Also, each winter, heavy snow may push the tree's low-lying branches to ground level, where they take root and survive to grow again the next year in a process known as layering. Layering occurs when a tree's branch comes in contact with the earth, and new roots sprout from the contact point. Other trees, such as coast redwoods and western red cedars are known to reproduce by layering. The tree's age was determined by carbon-14 dating of the root system, which found roots dating back to 375, 5,660, 9,000, and 9,550 years.

Previous researchers considered the Norway spruce species to be a relative newcomer to Sweden, with theories postulating the tree migrated into the area around 2,000 years ago. Trees much older than 10,000 years would be practically impossible in Sweden, because until around 11,000 years ago the area was in the grip of a world-wide ice age. If you're ever in Sweden's Dalarna province it's worth a visit as it's a chance to see one of the oldest living trees on the planet. There is a small path leading up towards the tree, however, it is unmarked, as park rangers do not want to encourage large groups of tourists to surround the tree.