On average, a real Christmas tree can last between 4-6 weeks before it starts to show signs of drying out and losing its needles. The length of time that a tree will last depends on various factors such as the tree's freshness, species, and how well it has been cared for. For example, Fraser firs tend to have a longer lifespan than other varieties due to their thick needles and strong branches. To ensure the longest lifespan possible for a real tree, it's important to keep it well hydrated and away from heat sources such as fireplaces or heating vents.