Thanks Bee! I'll dig into these!
edit: I played a bit with the scaling demo you posted, and it appears the trees can't actually trigger a collision event. It seems as though what is actually happening is that the static tree to the left of the view actor is the only 'real' tree, and the scaling ones are just images of it. I guess that to make a colliding, scaling actor, you'd have to make a scaled image of an actor follow over the real actor who is nearly perfectly transparent, and then have several sizes of the original actor art that changes with the scaling of the image. Kinda defeats the purpose.
On to rotation...