"The Last Dream of the Old Oak" (Danish: "Det gamle egetræs sidste drøm") is a children's fantasy story by Hans Christian Andersen first published in 1858. The tale is alternatively titled in English as "The Last Dream of the Old Oak Tree."
The story begins with an old oak tree who is three hundred and sixty-five years old. Unlike humans, who are awake by day but sleep at night, trees stay awake through three seasons of the year but sleep through winter. During the summer, the oak tree would speak with the Ephemora, a species of fly which lives for only one day. The oak tree would lament that they only had a single day to live, and suggest that their lives must be filled with such melancholy. The flies would invariably refute him, saying that their lives were filled with many moments of beauty. They claim that the beauty of the world does not end upon death, and that the flies measure time in moments rather than the tree's years, so the flies and the oak tree have the same amount of time to live; they only reckon it differently. The oak tree has this conversation many days in the summer with each subsequent generation of Ephemora.
As the seasons pass and winter approaches, the oak tree prepares to sleep for the winter. As the oak tree falls into sleep, it has a magnificent dream. In the dream, the church bells ring as if it is Christmas time, yet the season is warm and balmy as if it was summer. The oak tree begins reliving its life in the dream. Knights and ladies pass through the forest, and soldiers set up camp beneath his branches. Time continues to pass, and young lovers carve their names into his bark. The tree continues to grow taller and deeper, as he sees every person who wandered by, and every plant which grew around him. The oak tree rejoices in being able to see all the life he has ever known in this one ephemeral moment, and questions how it is possible. The multitude of plants around him answers that it is possible in heaven. The oak tree finds itself stretching further up, until its roots are freed from the ground and the tree floats towards the sky. The oak tree is overwhelmed at being able to be with all those it ever loved in this single moment.
Simultaneously, in the real world, a great storm is raging. As the tree is dreaming of its roots being released and floating towards the sky, the wind pushes over the oak tree and tears it up by the roots. The tree lies dead. A ship full of sailors who survived the storm looks to the coast where the oak tree was and they lament its passing, having used it as a landmark for many years, and noting that none can replace it. They then sing a Christmas carol which celebrates the redemptive nature of Christ's love and the promise of eternal life.