A cat doesnt get stuck in a tree. A cat climes a tree to get away from something it is threatened by.
The reason the cat wont come out of the tree is because you are standing at the base hollering at it. He is trying to stay away from YOU!
If you just go home, the cat will come out of the tree when he is damn ready to.
If the cat sees someone that he actually wants to greet, then he will be one the ground before you can scratch the hair of his chinny chin chin.
You know, I'm not so sure about that. That's what I always thought, but someone recently explained to me that a cat's claws grow in such a manner that it's easy to climb a tree, but not to come down it. Hope they're wrong.