In Norse mythology,  Yggdrasil  is a central cosmic tree whose roots and branches extend to various worlds.

The gods 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.  

Image by Oluf Olufsen Bagge (1780-1836), Danish Engraver

Type of Custom: Tu B'Shvat Blessings

Holiday/Event: Tu B'Shvat

Source: Public Domain