Here’s something cool. Norway spruce trees sprout from subterranean root systems, and though the actual trees come and go, the roots are extremely long-lived. In this they’re actually a lot like mushrooms.
New research by Leif Kullman at the University of Umeå is just being reported on by the media. His team has studied spruce trees on the treeline of Mount Härjehogna in Dalecarlia, central Sweden, and found no standing trees older than 600 years when wood samples were dated. But below ground, the living roots of three trees gave radiocarbon dates at 5,000, 6,000 and 8,000 years BP! The oldest root system thus dates back from the end of the latest glaciation. It’s been supporting varying types of spruce, from little bushes to tall trees, as conditions have varied through the millennia.
(The only bits that are actually alive and metabolising in trees are the surface layer. Every year-ring gives a progressively older radiocarbon date as you move toward the centre of the trunk. That’s how it’s possible to use dendrochronology to calibrate radiocarbon dates.)
This offers a number of interesting new perspectives. Firstly, though the Norway spruce is a recent immigrant to much of Sweden, it is now in fact the oldest known tree species in the mountains of Dalecarlia. Secondly, if we want to know what the Norway spruce genome was like 8,000 years ago, we needn’t look for deadwood in bogs. We can sample living individuals on Mount Härjehogna and elsewhere.