A real Christmas tree can last for several weeks, even up to a month or more if cared for properly. However, the exact length of time will depend on various factors such as the type of tree, the climate it is kept in, and how well it is maintained. It is important to keep the tree well-watered, ensure it is in a cool, dry place, and avoid placing it too close to a heat source such as a fireplace or heater. Additionally, it is a good idea to trim the tree regularly and dispose of it properly once it begins to dry out.