ok i read this form but didnt understand it 100%. If im in my tree stand that is 16 feet up and a deer comes to 15 yrds would i aim the same way as i would if i was on flat ground?? hope you can help thanks

Yes. Your yardage should be flat (base of tree to base of tree) or (16 ft up to 16 ft up) and you would aim as if you were on the ground. Its always a good idea to practice this at your house before going to the woods though. And if aiming at an alert deer, its a good idea to aim a little low. good luck!!

Make sure to bend at the waist , your yardage change will be minimal.
in your example if you used a range finder from the tree it would read 15.9 yards
nothing to change your pin placement

the physics of it says at that height, it's going to be within inches to a foot or two different, so just aim dead on as you would on the ground and pull the trigger!

that said, form changes can effect it, you should shoot a target from that height and see what happens. You could be a few inches high/low.

As mentioned, unless you're at some freakishly high height (e.g. 30 feet), the difference in horizontal distance due to your elevation is negligible. What's more important is to maintain your form when aiming at an angle towards the ground. Don't drop your arm, but bend at the waist. That's the reason most hunters shoot high from an elevated stand, not because they misjudged the distance.

Try it on a practice range and see the difference between dropping your arm and bending at the waist and you'll see what I mean.

Bending at the waist is key. When you go to shoot have a short list to follow for each shot.

For flat ground I like
ease (smooth draw)
anchor (kissing button and peep, lined up with my pin)
squeeze (squeeze the release and not snap my finger on it)

For elevated I add in "bend" after "anchor"

When a deer is in front of me I mentally tell myself to "calm down" That dump of adrenaline into the system can make you rush a shot from excitment.