The Party Tree was a large tree in the centre of the Party Field, south of Bag End in Hobbiton. It was presumably either a beech or oak, as many other trees were in the Shire. A pavilion was erected around the Party Tree and stood at the head of the main table during Bilbo's Farewell Birthday Party and lanterns were hung in its branches. Bilbo made one of his renowned long speeches under this tree upon his leaving of the Shire.
After the War of the Ring, Sam Gamgee returned to the Shire in November TA 3019 to find the tree had been felled by Saruman's orders and abandoned in the middle of the field. The tree was removed after the Scouring of the Shire, and in place of the original tree, Sam planted a silver nut given to him by the Lady Galadriel. Spring TA 3020 brought the first sapling of a Mallorn tree out of Shire soil. It was the only mallorn outside the great forest of Lorien, and people both Men and Elves came from miles around to gaze upon it.
It is thought that Tolkien got his inspiration from a willow hanging over the mill-pool at Sarehole, Warwickshire, England.
"They've cut it down!' cried Sam. 'They've cut down the Party Tree!' He pointed to where the tree had stood under which Bilbo had made his Farewell Speech. It was lying lopped and dead in the field... As if this was the last straw Sam burst into tears."
"One incident in particular remained in his memory: "There was a willow hanging over the mill-pool (at Sarehole) and I learned to climb it. It belonged to a butcher on the Stratford Road, I think. One day they cut it down. They didn't do anything with it: the log just lay there, I never forgot that."