The third element of Ygdrasil which we perhaps see making an appearance in Tolkien’s Lord of the Rings is the root of corruption, the root being strangled and bitten by Nidhogg the serpent. This tortured root, since it is on the tree that represented all existence, is a symbol of how misery and evil are rooted in the world. Similarly, the tree that we know as Old Man Willow has been corrupted. He is face of the evil that lurks in the hearts of many trees in the wood that Tom Bombadil rules over. Tom Bombadil himself is a Valar governing this wood, just as Mimer who rules over the grove of the third root and its well is a god.
Perhaps this connection is a little tenuous. But it is clear elsewhere that this story of the root tapped by a corrupt creature has left its mark on Tolkien. In the Silmarillion, we see that the two trees Telperion and Laurelin, the massive trees that light the world, are destroyed at Melkor’s behest, when he brings Ungoliant, the massive she-spider. Ungoliant kills the trees by biting into their roots and sucking the life out of them. It is true that Nidhogg the serpent has been exchanged for a spider, and that this is a one-time attack, not a permanent state of affairs: but nonetheless, the significant elements marking the tale are unchanged. A terrible monster stealthily attacks an essential piece of the cosmic architecture, a component of the world’s own structure, in the shape of a tree. And despite this attack, the serenity of the divinely planted system is preserved. In Ygdrasil, the tree’s life is maintained by the care of the guardian, Mimer, the God of wisdom and knowledge. In the Silmarillion, the light of the two trees is salvaged, and preserved in the form of Telperion’s last flower and Laurelin’s last fruit, by the Valar Yvanna. The flower and fruit are now the moon and sun, out of reach from attack, and safe forever. In this way, we can see a fairly obvious influence of the old Norse tale upon the work of Tolkien. While his creation tale preserved itself from the pagan elements of Norse mythology (something that Tolkien did quite deliberately, and rejoiced in ), his later tales delve into the richness of the Norse tradition.
It is no accident that Tolkien wrote a whole book called Tree and Leaf. It is plain that the Norse cosmology, based in the form of a tree, took hold of his mind. Tolkien characterizes the collection of Tales that mankind has created as a tree, un-ravelable, complex, and alive. This tree is eternal, and the tales that spring from it are endless. In this tree, this living fountain of tales, we see another Ygdrasil. Tolkien sees himself as plucking leaves from an infinitely fantastic and rich source. Not only does Ygdrasil inhabit the worlds that Tolkien subcreates, but it is from a sort of Ygdrasil that Tolkien gets his tales: grown from the soil of England and rooted in old traditions: one of Tolkien’s roots is clearly the Norse mythology of Ygdrasil.