Yggdrasil, the World Tree in Viking mythology, grew on an island surrounded by the ocean, in the depths of which the World Serpent lay. This ash tree's trunk reached up to the heavens, and its boughs spread out over all the countries of the Earth. Its roots reached down into the Underworld. A squirrel ran up and down the tree carrying messages from the serpent gnawing at the roots to the eagle in the canopy, and back. A deer fed on the ash leaves and from its antlers flowed the great rivers of the world. A magical goat grazed by the tree, and its udders dispensed not milk but mead for the warriors in Odin's Great Hall. The gods held their councils under the canopy of their guardian tree.
Odin, the foremost god of the Vikings, hung himself on Yggdrasil as a sacrificial ordeal, during which he lost an eye to ravens. Ultimately though, he was rewarded with insights and wisdom, notably knowledge of the system of the Runes. Both he and Thor, the god of thunder, were said to possess magical spears made of ash wood. Mortals' spear shafts were also typically made of ash (as were bows, in the absence of yew, and arrow shafts). The words for ash and spear seem to be related in that a poetic Anglo-Saxon word for spear was aesc and the Norse word for ash was ask (influencing Highland place names such as Port Askaig). The Vikings were also referred to as the Aescling meaning 'Men of Ash'.
Like the Vikings, the Gaels also thought of the ash tree (which they called uinsinn, pronounced ooshin) as protective. Of the five legendary guardian trees of Ireland, three were ash. Ash is also the second most popular tree growing beside Irish holy wells, and on the Isle of Man ash trees were said to protect the purity of springs. In England the ash is the commonest tree as a place name element after the thorn.
In British folklore the ash was credited with a range of protective and healing properties, most frequently related to child health. Newborn babies were popularly given a teaspoon of ash sap. Ailing children, especially those suffering with rupture or weak limbs, would be passed naked through a cleft in an ash tree or ash sapling, to cure them. The cleft was often specifically made for the purpose and bound together again after the ceremony to heal over as the child also healed. Some folklore then suggested an intimate bond between the welfare and fate of the now related tree and person, with harm to the tree being reflected in the healed person's life, leading people to become understandably protective of 'their' ash tree.
Though there does not appear to be any religious reason why this tree should be associated with Ash Wednesday, the mere association of the words is obvious, and in parts of England children used to bring a twig of black-budded ash to school on this day. Any child who failed to remember this risked having his or her feet stomped on by other ash-twig-bearing children!
Ash wood is very strong, tough and elastic, and it is said that a joint of ash will bear more weight than any other wood. Chariot and coach axles were made of ash as were oars, tool handles and the weaponry already mentioned. The tree coppices well, giving strong straight poles for bean poles after five years or oars after twenty. Ash coppice stools seem to be able to go on producing poles almost indefinitely and an eighteen-foot-diameter stool in Suffolk has been estimated to be over a thousand years old. The density of the wood also makes it an ideal fuel, as is reflected in its Latin species name Fraxinus meaning firelight. One of the traditional woods used as the yule log was ash. In some areas the 'log' was actually a faggot, that is a tightly bound bundle of coppiced ash rods. To this day ash is the most highly valued firewood, burning for a long time with an intense heat, whether seasoned or green.