From the Editors of The Daily Cat
Most cats cannot descend a tree safely, because it's easier for a cat to climb up, using its claws and muscular hindquarters. When descending, the cat must rely upon its weaker front paws, with claws naturally facing in the wrong direction. A cat left to its own devices may even try to back down a tree.
This problem usually occurs when something or someone frightens the cat. A tall tree may provide the only means of escape. Some owners have even resorted to calling their local fire department to help get their cat down without injury. A better solution is to keep your cat inside, where the risk posed by tree climbing is eliminated.