The answer, my curious friend, is that you only need one dark oak sapling to grow a tree. Yep, just one little guy can turn into a beautiful, towering tree, given the right conditions, of course. It's kind of like how a small seed can grow into a huge pumpkin, right?
But, here's the thing, just because you only need one sapling, doesn't mean you shouldn't have a few backups, just in case. I mean, think about it, if you only have one sapling and something happens to it, like a pesky rabbit comes along and munches on it, you'll be left with nothing. It's like having just one egg in a basket, you know?