Editing World tree (section)

===Norse mythology===
In [[Norse mythology]], [[Yggdrasil]] is the world tree.<ref name=Kuperjanov2002/> Yggdrasil is attested in the ''[[Poetic Edda]]'', compiled in the 13th century from earlier traditional sources, and the ''[[Prose Edda]]'', written in the 13th century by [[Snorri Sturluson]]. In both sources, Yggdrasil is an immense [[Fraxinus excelsior|ash tree]] that is central and considered very holy. The [[Æsir]] go to Yggdrasil daily to hold their courts. The branches of Yggdrasil extend far into the heavens, and the tree is supported by three roots that extend far away into other locations: one to the well [[Urðarbrunnr]] in the heavens, one to the spring [[Hvergelmir]], and another to the well [[Mímisbrunnr]]. Creatures live within Yggdrasil, including the [[Deer|hart]]s [[Dáinn, Dvalinn, Duneyrr and Duraþrór]], the giant in eagle-shape [[Hræsvelgr]], the squirrel [[Ratatoskr]] and the [[Norse dragon|wyrm]] [[Níðhöggr]]. Scholarly theories have been proposed about the etymology of the name ''Yggdrasil'', the potential relation to the trees [[Mímameiðr]] and [[Læraðr]], and the [[sacred tree at Uppsala]].