Why is it that Yggdrasil - the World Tree - is often seen as a horse? Many folk even translate the name to mean 'Ygg's Horse'. Ygg is a name used by Odin and Drasill is used to mean Horse.
The most common view is that the World Tree is an Ash tree. Here we may have a very old word play as there are many examples of the word 'Ash' being used as a name or prefix for horse. The (grand)son of Hengest was a king called Oeric. He used the title Oisc which was the same as Aesc which means Ash. Hengest and Horsa were the Anglo-Saxon chieftains who led the Germanic tribes to Britain. We know that Hengest and Horsa were war-titles and not real names, and it seems that Oeric continued this tradition. Hengest means Stallion, Horsa means Horse, as does Ash. To many English Wodenists Hengest and Horsa are viewed as Divine Twins, which itself is a recurring archetypal theme which runs throughout Aryan history. The Horse gods of the Baltic lands are viewed as twins and are called the Ašvieniai, in Aryan-Hindu lore they are called the Ashwins. Both set of names derive from the word Ashva which means Horse. What is interesting is that the word Ashva cognates with the Germanic word Ehwaz which means horse. The Anglo-Saxon word for horse was Eoh, and ēoh means Yew. Further to this the word 'yggia' comes from the root *igwja which again means Yew-Tree. It would seem that both ideas of the World Tree being Ash or Yew derive from older words meaning Horse.