Well this is going to be a tough one!
About 8-9 years ago I was visiting a friend's house and her mother was about to order a pay per view movie, MONKEYBONE to be exact.
The movie didn't start right away but rather a short film played before the feature presentation began. It was CGI animated and it was of a very creepy, abstract-looking girl running from a home I believe… I'm not entirely sure. Well she runs up to this tree and hands spring out of the bark.
I don't really remember a lot of the details because I was 8- and closed my eyes through most of it.
Sound familiar? It's been bugging me for years.
I don't know the animation you're referring to specifically, but I can suggest this clue: "Monkeybone" was directed by Henry Selick, who also directed "James and the Giant Peach" and collaborated with Tim Burton on "The Nightmare Before Christmas." I would check the extras on the DVDs of "Monkeybone" and other films put out by this animation shop, including "Corpse Bride," and maybe the one you remember might be in there somewhere. Actually, the first thing that came to mind from your description was "Sleepy Hollow," which wasn't animated, but I seem to remember a scene where hands come out of a tree groping for Christina Ricci.