Surely a pilot should have information as to all of the charted obstacles relating to their approach?
Yes, but we are also talking about living creatures here.
They grow, they stop growing, bits fall off them they are bigger when they have leaves and smaller when they lose them.
They grow no more than a few feet a year so there is no point in chasing exact heights when you are not supposed to come within 100 feet of them in the first place?