Nion (Ash) Tree
The Ash (Nion in Gaelic) can grow to great heights (200 feet or more). To sustain that height, an Ash tree must have a massive root system. To the Celts, the tree is/was related to the need to be well grounded as one seeks/sought spiritual enlightenment. Wood from the ash burns with great intensity helping Celts in a variety of ways. Its massive size is comforting in a certain sense and may be why the Ash is a symbol of protection...especially for children.
The N for Nion (Ash) in Ogham script appears in the accomanying illustration. As we work our way through the 20 letters in the Ogham alphabet, one gets a sense of how these characters are linked to the trees they are associated with. When a reference to the Ash appears in a story for instance, one might expect a need for protection to arise in subsequent sections of the story.