No. I'd be shocked if an apple tree started growing in a forest because someone chucked a core back there. Apple trees... kinda suck, they aren't very robust and they grow best in full sun. With that said I do agree in principle that people should be more careful with invasive plants I just dont see apples outcompeting actual forest trees in a forest. Also they can't self pollinate so that tree wouldn't be able to produce fruit and future apple trees anyways.