Tree age and flavor?

I think one difference has to do with the size of the root system. An older tree should have a bigger root system than a younger tree in most cases. There may be some other differences as well. I imagine that you could look at the information about vines for wine (old vine vs. new), about which there is probably more information available in English.

But honestly, this is probably a question better asked to a farmer than to people on an internet newsgroup. Many people may claim to have an answer, but a lot of the information that's out there is put there by vendors who are either repeating what they heard, or who have some sort of sales agenda to push.