Hilda Ellis Davidson says that the notion of an eagle atop a tree and Nídhöggr coiled around the roots of the tree has parallels in other cosmologies from Asia, and that Norse cosmology may have been influenced by these Asiatic cosmologies from a northern route. On the other hand, Davidson adds, some Germanic peoples are attested as worshipping their deities in open forest clearings, and that a sky god was particularly connected with the oak tree, and therefore "a central tree was a natural symbol for them also".Davidson (1993:69).
