I do real well between 10-15 feet. I can't imagine being 45 feet up in a tree with a bow, that's what, 4 or 5 stories high! I like to take my shots inside 25 yards, preferably within 20. If 15 yards up I would already be close to my limit when the deer is right below me. I think the angle of the shot, when that high, makes double lung hits nearly impossible. The kill zone gets reduced greatly also.
Why are you climbing 30 feet high now? If you are wondering if it is too high, I would say that it is. Confidence is very important when good shot placement is needed. There are less branches in the way when you stay a little bit lower also.
I got a doe with my flintlock from a 10 foot high stand just last Thursday. The group of deer never knew I was there, despite the florescent orange requirement.