My high level monk has a 10 foot vertical jump (taking 10)... does he take falling damage if he jumps up and then falls back to where he jumped from?
Yes. Jumping up 10 ft, you will naturally fall 10 ft, but since you deliberately jumped, you will take 1d6 nonlethal damage.
Jumping up 10 ft. is an Acrobatics DC 48 check.
However, if you can jump that high, you have a good chance to soften your fall with an Acrobatics DC 15 check and take no damage.
Right, I was attempting math in the morning and my brain did something wonky.
Jumping up 10 feet is an Acrobatics DC 40 check (DC 80 without a running start).