I have discovered that dark oak saplings won't grow in to trees in other environments like other saplings. I went in my creative world and bone mealed every tree's sapling on normal plains grass. They all grew in to trees (Jungle, oak, spruce, birch, acacia) except for dark oak. All the other trees used probably at the most 10 bone meal, before growing in to a tree, but the dark oak sapling I've used more than a stack of bone meal and it's still a sapling. As I want to build with dark oak, and am not near any dark oak forests, I would appreciate if this could be fixed.