Here’s an interesting story about how apple production has changed due to changes in how the trees are grown using new dwarfing rootstocks.  The example is from Washington State, but I’m sure that this change in management style is occurring all over the US.  You can read it at NPR here.

A modern orchard near Wenatchee, Wash. The trees in the foreground have just been planted. In the background, an orchard of young trees.
Dan Charles/NPR