The lifespan of a real Christmas tree can vary depending on several factors, such as the species of tree, the care it receives, and the environmental conditions. In general, most real Christmas trees can last anywhere from one to three weeks after being cut down. Some tree species are hardier and can last longer, such as Douglas firs, while others may not last as long, such as pines. It's important to properly care for your real Christmas tree to extend its lifespan, such as keeping it hydrated and away from heat sources.