In 2008 a 9,550 year old spruce in the Dalarna province of Sweden was proclaimed the world’s oldest recorded tree. Yet for many years the spruce tree had been regarded as a relative newcomer in the Swedish mountain region. How could these two facts correlate? It all comes down to clones.
The journey began when a fascinating discovery was made under the crown of a spruce in Fulu Mountain in Dalarna. Scientists found four ‘generations’ of spruce remains in the form of cones and wood from the highest grounds. The discovery showed trees of 375, 5,660, 9,000 and even 9,550 years old – and everything displayed clear signs that they had the same genetic make-up as the trees above them. Since spruce trees can multiply with root-penetrating branches, they can produce exact copies; in other words, they can clone.
‘The results of our research have shown that, in actual fact, the spruce is one of the oldest known trees in the mountain range,’ says Leif Kullman, Professor of Physical Geography at Umeå University.
In the Swedish mountains, from Lapland in the north to Dalarna in the south, scientists have found a cluster of around 20 spruces that are over 8,000 years old. Although summers have been colder over the past 10,000 years, these trees have survived harsh weather conditions due to their ability to push out another trunk as the old one died.
The tree now growing at Dalarna, and the wood pieces dating back 9,550 years, have the same genetic material, as has been shown after wood testing by Carbon-14 dating at a laboratory in Miami, Florida. Previously, pine trees in North America had been cited as the oldest in the world – coming in at between just 4,000 and 5,000 years old.
‘The average increase in temperature during the summers over the past 100 years had risen one degree in the mountain areas,’ explains Kullman. ‘Therefore, we can now see that these spruces have begun to straighten themselves out. There is also evidence that spruces are the species that can best give us insight about climate change.’
The ability of spruces to survive harsh conditions also presents other questions for researchers. Did the spruces actually migrate here during the Ice Age as seeds from the east, travelling 1,000 kilometres over the inland ice that then covered Scandinavia? Do they even really originate from the east, as taught in Swedish schools?
‘My research indicates that spruces have spent winters in places west or south-west of Norway where the climate was not as harsh in order to later quickly spread north along the ice-free coastal strip,’ suggests Kullman.
‘In some way they have also successfully found their way to the Swedish mountains.’
Ref. Swedish Research Council