Yggdrasil

The conception of the tree rising through a number of worlds is found in northern Eurasia and forms part of the shamanic lore shared by many peoples of this region. This seems to be a very ancient conception, perhaps based on the Pole Star, the centre of the heavens, and the image of the central tree in Scandinavia may have been influenced by it....

Among Siberian shamans, a central tree may be used as a ladder to ascend the heavens.

(Print: Friedrich Wilhelm Heine)