I'm an idiot.
Last year, I planted an Anna apple tree and a Dorsett Golden apple tree. Unfortunately, one of the trees isn't doing so well (seems to have some sort of disease affecting most of the canopy). I've decided that if it doesn't roar back in the spring, I'm going to replace it. The problem is, I've forgotten which tree is which, so if I try to replace the one that's not doing so well, I have a 50/50 chance of getting the wrong variety. Is there any way to tell these two varieties apart without waiting for fruit?