I have five apple trees growing on my property (that I know of) that were obviously seeded from animal droppings, each produces different fruit in abundance but not worth eating by humans, all small, mishapen, dry, and extremely sour fruit... but the critters definitely enjoy partaking. I toss apple cores from perfectly good fruit off my back deck all the time, I've seen the deer eating their prizes. I'm positive that's how those freak apple trees come to grow on my property, probably from someone elses cores, I haven't been here long enough for my cores to have produced such large trees... and critters travel long distances to forage, those apple seeds could have come from miles away. I had a great uncle whose hobby was growing miniature landscapes is tiny pots, some in toothpaste caps, he would plant the seeds from fruit he bought, apple, pear, citrus, they grew and some even produced fruit, but none one would eat. You have better odds of winning the lottery than of planting apple trees from seed that produces edible fruit.