This tree, a reminder of the elves and the light of Valinor, was considered one of the most valuable things brought to Gondor after the fall of Númenor. It became a symbol of the royal line, which was prophesied not to end as long as the tree lived.

An image of this tree was used on the banners and sheilds of Gondorian soldiers.

The tree originated from Nimloth (the White Tree of Númenor) which itself had originally come from Galathilion. Galathilion was created for the Vanyarin and Noldorin inhabitants of the town Tirion in Valinor by the Vala Yavanna as a copy of Telperion, one of the Two Trees of Valinor. Galathilion was smaller and didn´t have any light of its own.

Nimloth stood in the courtyard of the king´s palace in Armenelos until the last king of Númenor, Ar-Pharazôn, who had been deceived by Sauron, was persuaded to cut it down. He was first reluctant to do so, since he knew about the prophesy. The wood was burnt on the altar of the temple Sauron built to Melkor (Morgoth). Before this happened, Isildur managed to steal one of the tree's fruits and its seed was planted.

After the fall of Númenor, the sapling from Nimloth was brought by Isildur to Minas Tirith, where it and its saplings grew until what was thought to be the last one died in 2852 at the same time as the 21st Ruling Steward of Gondor, Belecthor II. No sapling could be found, so the dead tree was left to stand "until the return of the king". A sapling was finally found by king Aragorn in the mountains and planted instead of the dead one. The white tree had survived, and with it, the royal line.
Encyclopedia entry originally written by Malinornë