The lifespan of a Christmas tree can vary depending on several factors such as the species of tree, its age, its care, and its environment. Generally, a healthy Christmas tree can last anywhere from four to six weeks, with some species even lasting up to eight weeks or more. However, it's important to note that a tree can start to deteriorate more quickly if it's not properly cared for. Proper watering, regular trimming, and placement in a cool, dry location can all help extend the life of a Christmas tree.