Omnicron, excuse me if I'm wrong, but if you can get another tree that isn't apple oak to produce apples via crossing genes (there was this post of a guy somewhere that made this tree with max fruit production, max leaves, max everything, really), you can get the orchard to work on it.
I believe that guy made his trees for use in an arboretum though, since he wanted biomass - ergo, saplings. That means he would choose a tree that also drops the apples from decaying leaves (instantly, without having to wait for them to mature), because those apples let him run the fermenter for free and also boost his biomass yield by 50% with fruit juice. For that reason I am not sure if that kind of tree actually
would work in an orchard. if it did, it would mean that you can not only swap behaviors, but that you can in fact have
both behaviors at once. I was hoping to find someone who would be able to say "I have done this before and the result was this".
Also, I have never seen any examples of someone doing the opposite - i.e. using a different fruit than apples, for instance. Why is that?
I can of course test myself if necessary, but I have limited playtime and I still haven't even bred all the tree species I'd need for such a test. It would take me quite a long while.