Shooter is 18 feet up:

Ranged distance from treestand: Actual distance to game animal:
20 yards 19.07 yards
25 yards 24.26 yards
30 yards 29.39 yards
35 yards 34.48 yards
40 yards 39.54 yards

Shooter is now 21 feet up:

20 yards 18.73 yards
25 yards 24.00 yards
30 yards 29.17 yards
35 yards 34.29 yards
40 yards 39.38 yards.

Normal bowhunting heights and ranges.