Yggdrasil, the Tree of Life, is not only one of the most well-known Viking symbols/Norse emblems but an important fundamental of the Norse principle itself.
Basing on Norse folklore, Yggdrasil is the Great Tree that ties in with the nine worlds/nine realms of the galaxy, namely Asgard, Midgard, Muspelheim, Jotunheim, Vanaheim, Niflheim, Alfheim, Svartalfheim, Helheim.
That is the reason why Yggdrasil is regarded the emblem of the interconnectedness of all things in the world.
Yggdrasil fills in a spring based on the Norse religious belief which suggests all life arises from the water. That is just one of the reasons why it is known as the Tree of Life.
The second explanation is that it is believed for Yggdrasil's fruits to provide youth for the gods, 'giving them life'.
According to Norse folklore, the whole world will end with Ragnarok, a battle between gods with only a man and a woman staying alive it by covering inside the hollow of a tree. The couple will leave the tree to bring life back again to the world. Although the tree in question is not pointed out particularly or Yggdrasil is not clearly related to the myth, it is strongly believed by some to become the tree that will protect life from Ragnarok.
This symbol is used by Bavipower to design many impressive Viking Jewelry such as Yggdrasil Tree Pendant Necklace.