“This gives us a completely different picture of how spruce first came to Sweden after the last Ice Age,” researcher Leif Kullman told The Local.
Kullman, a professor at Umeå University's Department of Ecology and Environmental Science, was part of a group of scientists carrying out an environmental research project in near the Härjehogna valley in Dalarna in central Sweden.
Carbon-14 dating tests carried out by a lab in the United States on three spruce tree root samples revealed that the trees' roots were 5,000, 6,000, and 8,000 years old, reported Svergies Television's local news program Gävledala.
Kullman explained that, while any individual tree growing in the area would itself not be more than a few hundred years old, any tree found on site over the centuries would be generated from the same genetic root system.
“There is constant turnover in what is actually growing above ground,” he said.
“But genetically, the trees growing today are the same as those from thousands of years ago.”
Prior to the finding, researchers had estimated that spruce trees had only been growing in Sweden for about 3,000 years, Kullman said.
“The finding has changed our world view, so to speak,” he added.
He said it remains unclear exactly where the trees came from following the melting of the ice which covered much of Sweden around 10,000 years ago. Some theorize that the trees migrated from Russia in the east, but Kullman said nothing has been proven for certain.
“It remains an open question,” he said.
According to the Guinness Book of World Records, the oldest living individual tree is a bristlecone pine in California's White Mountains estimated to be 4,733-years-old.