The Zombie Pigmen invasion in the Second Age reached the entire way into Ajury. They invaded and using all the lava at their disposal, burned the World Tree almost to the ground. Fortunately, the tree lived for a short time longer, allowing the Arbor Druids to do the Ritual of Regrowth, and gain a new World Tree Sapling, to plant and replenish their Arbor Druid Magic.
