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The world's oldest tree has been found in Sweden, a tenacious spruce
that first took root just after the end of the last ice age, more than
9,500 years ago.
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| The tree has rewritten the history of the climate in the region |
The
tree has rewritten the history of the climate in the region, revealing
that it was much warmer at that time and the ice had disappeared
earlier than thought.
Previously, pine trees in North America were thought to be the oldest, at around 5,000 years old.
But Swedish scientists report that in the mountains, from Lapland in
the north to Dalarna in central Sweden, there are much more ancient
spruce trees (Picea abies).
Prof Leif Kullman at Umeå University and colleagues found a cluster of around 20 spruces that are over 8,000 years old.
The oldest tree, in Fulu Mountain, Dalarna (“the dales”), was dated by
carbon dating at a laboratory in Miami, Florida to 9,550 years old and
around it were generations of clones 375, 5,660 and 9,000 years old
that have the same genetic makeup.
The clones take root each winter as snow pushes low lying branches of
the mother tree down to ground level, explains Prof Kullman.
“A new erect stem emerges, and it may lose contact with the mother tree over time.”
The trunks of the mother tree would survive only around 600 years but the trees are able to grow a new one, he adds.
The finding is surprising because the spruce tree has been regarded as
a relative newcomer in the Swedish mountain region and is thought to
have originated 600 miles away in the east.
"Our results have shown the complete opposite, that the spruce is one
of the oldest known trees in the mountain range,” says Prof Kullman.
Ten millennia ago, a spruce would have been
extremely rare and it is conceivable that the ancient humans who lived
there imported the tree, he says.
“Man immigrated
close to the receding ice front. We have also found fossil acorns in
this area, and people may have taken them with them as they moved over
the landscape.”
It had been thought that this region was still
in the grip of the ice age but the tree shows it was much warmer, even
than today, he says.
“Spruces are the species that can best give us insight about climate change,” he says.
The
summers 9,500 years ago were warmer than today, though there has been a
rapid recent rise as a result of climate change that means modern
climate is rapidly catching up.
The tree probably survived as a result of
several factors: the generally cold and dry climate, few forest fires
and relatively few humans.
Today, however, the
nature conservancy authorities are considering putting a fence around
the record breaking tree to protect it from trophy hunters. Source
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