Calculations... I did a few more calculations out using a height of 24' and the trend is as you progressively get further away from the tree...the ACTUAL yardage difference with angle included decreases: 20yds = 21.54yds 25yds = 26.25yds 30yds = 31.05yds 35yds = 35.90yds 40yds = 40.70yds Unless the deer jumps the string you should aim just about the same as if you were on the ground...the distance differences are too small...average arrow is is 28" right? So roughly 2 arrow lengths in distance will not change the arrows flight pattern unless it hits a branch or something.
Experience shows small angular differences do not make large impact changes; however, radical angles (such as shooting up the side of a mountain or drastically down from a high tree stand) will make significant impact point changes. The actual distance from the base of the tree to target and not line of sight (hypotenuse) is what really matters. If these angles made no significant difference, the advent (and popularity) of angle compensation range finders would never arisen. The main thing to remember is when shooting steep angles, aim lower than you would normally.
The yardage discrepancy actually will become less as the yardage increases. your angle/trajectory is closer to 0% as your target gets farther away.
You don't say what type terrain you will be hunting. The difference can be more substantial if your tree stand is on a hill side and the deer is below or above you. This is where the new range finder that take angle into affect. You could have the horizontal distance to an animal be half the actual distance. You would need to aim the horizontal distance. I usally range to to the upper section of trees when I first get in my stand.
