The Oiolaire was a tree that originally grew in the Undying Lands. Its branches were used to make Elven ships. It was located near the sea. It was moved to Numenor where it was also used to build ships. When the Numenoreans set out for Middle-Earth, they called the branch of the Oiolaire the "Green Bough of Return." This token was placed in the front of the ship by the wife of the captain. It never fell or broke if it was damp with water from the Great Sea. But one day, Aldarion was sailing and was blown north. The bough was broked and he had to return to Numenor, which was in a sense a good thing because his wife Erendis was upset with him.