I just prune the old trees, I haven't planted any, but as I understand it all apple trees in common use are grafted. You take a hardy rootstock and graft the kind of apple tree you want onto it. That's why new shoots coming up from the roots need to be cut back, because they won't produce any useful fruit.
We get down to around 30 below here from time to time, so we need hardy stock, but that's still quite a ways above 50 below.
I grew up in upstate New York, where domestic and wild apple trees are everywhere.
The wild varieties tend to be a bit softer than the hybrids but they are extremely sweet and seem to ripen overnight. They don't store well, except when they got 16 inches of snow over them.
Pretty much the same with the pears, but they are usually harder and last longer.
I miss the black raspberries.