People that say it doesn't matter don't sit high. I'veHEARD for every twenty feet you go up it changes the distance one foot. Is this right? Probably not, but I reallyhave noidea, but height does matter. 15 feet, probably not. 40 feetabsolutely. Like badger said it's trig, but only to a point. If you're10-15 feet in the air, you're too close to theground. You're still shooting on a parallel plane of the ground to make a difference with modern bows. You've sighted in on that plane. If you're forty feet in the air the distance is no longer the same as the base of the tree to the target. When you really start to get up is when the distances start to change, plus gravitycan take affect, as well as wind. Does anyone really sit highenough to make a difference? Probably not sodon't worry about the issue.