Practicing from a treestand can be very beneficial

For example... if you are 30 feet up in a tree and the deer is 20 yards (60 feet)out from the base of the tree your straight line distance from you to the deer is 22.3 yards. If you shoot for 22 yards you will hit high. On a steep angle like this 2 yards can make a difference in a great hit and a marginal hit.

If the deer is only 15 yards (45 feet) out from the base of the tree he will be 18 yards from you. This will cause an even higher impact.