I was once called to rescue a lady's cat who sat stranded on the roof. When I put my ladder against the gutter, the cat raced to the other side of the roof and glared at me. The cat hissed at me when I approached him and then ran to another side of the roof. The cat and mouse game continued until he jumped on a tree, climbed down, and disappeared. Both the lady and I felt a little stupid.
Trees provide nesting sites for a variety of animals.
A cat might decide to hunt in trees for food or to just quench the natural hunting instinct. If this is the case, a rescue attempt might prove unsuccessful as the cat flees the climber's approach. A cat might even use a tree to escape the clutches of human hands. Animal control officers have reported incidents of chasing stray cats which often end in an aborted attempt when they climb a high tree. I personally remember a particular cat rescue that turned out being a cat escape.