The amount of time a Christmas tree can last without water depends on several factors, including the type of tree, its freshness, and the environment in which it's kept. A typical Christmas tree can last for several days without water, but it can start to dry out and lose its needles after a few days. To prolong the life of a Christmas tree, it's important to keep it well-watered and in a cool, moist environment. If you notice that the tree is starting to dry out, you can add a little bit of water to the base or mist it with a spray bottle.