Yes.
(Thats the short answer)

It depends on a lot of things, such as how high up you are in the tree, how steep an angle you are shooting, the range you're shooting at, etc. In my experience, if the shot angle isn't very steep, then the difference in arrow POI isn't very much. But if you're up 20 or 25 feet and shooting at a deer 10 yards away, then yes, it makes a difference. For me, shooting at a steep angle, especially at a close target, the arrow hits high (compared to shooting from the ground).

You really need to practice shooting from a treestand at a target- you may need to adjust your sights a little bit.