Thanks Dan - I wasn't completely aware of that.

In my situation, I'm trimming out dead branches, suckers, and long horizontil growth, sometimes on old growth apple trees, but usually on the young, wild trees - maybe 10-15 years old - Any specific advice for an apple tree that has never been pruned - some over 50 years old - or for the 10-15 year old tree getting its first "cutback"?