There are a great many wild apple trees where I live, in an almost endless variety. The majority of them are quite tart, but I've found a way to use them just the same. I came across this tree a few days ago which I guess is some variety of crab apple as the fruits were about 1 1/2- 2" in diameter. It had a very nice crop on its branches.... Since this is a wild tree it's never been sprayed and there were some apples with worm damage. I cut the damaged parts way and sliced the rest into a baking dish... Then added a bit of water and baked at 350* for an hour... After which I mashed them with a serving spoon. I added nothing (I don't have much of a sweet tooth). The baking took the edge off the tartness and now they can be used as apple sauce. Super tasty compared to store bought, and free!