Although there are a number of different views on this subject, this is what I have found to be the case: 1) You will have a tendency to shoot slightly high at close targets from a tree stand - what defines "close" is largely dependent on the speed of your bow, i.e. faster bows won't shoot as high as slower bows at close range; 2) It is the horizontal distance (from the base of the tree you're in) to the target that should determine the range of your shot; 3) The effect of horizontal versus slant distance to the target decreases with longer range; for example, you could probably hold right on a deer at 35 yards with a typical modern setup, whereas you might have to hold a shade low at 7 yards. Hope this helps, and good luck in Kansas - get a big 'un.
Venado muy grande!