The tree was first put up in the Octagon in 2004, after it was given to the city by the Caversham Foundation.
It is stored at Tulloch Transport during the year in two shipping containers, which will be placed beneath the tree and dressed to look like presents.
Several cross-street garlands have been installed across George St.
More will be placed across Princes St.
The one-tonne tree will remain in the Octagon until New Year's Eve.