The Dead Tree (T.A. 1640 -- 2872; the snag stood for 147 years) was planted by King Tarondor. It was the third and last White Tree of Gondor. It died at the same time as Belecthor II the twenty-first Ruling Steward.
For lack of a seedling, the Dead Tree was left standing in the Court of the Fountain of Minas Tirith for the following centuries and throughout the War of the Ring. That was until King Aragorn Elessar found a new seedling on Mount Mindolluin in 3019.