The mythical Norse tree Yggdrasil, also known as the tree of life does not appear to have a date of origin. There is no definitive date of creation that is documented, nor is one even loosely alluded to.
Learning how to pronounce Yggdrasil can be tricky if you've never heard it spoken aloud before, because it's not a word that sounds the same as it's spelled. The correct pronunciation would sound similar to eeig-dra-seal (Rolling the “r” in “dra” if you want to sound fancy), broken into 3 syllables.