Minecraft wiki entry for Tree_farming, associated text: Aside from the saplings, make sure there are no blocks less than 2 blocks away from the saplings (even torches), at any height up to the future height of the tree trunk (up to 32 blocks). A huge tree needs a 2×2 thick trunk to grow. These trees average ~96 wood (1½ stacks), and some can exceed 2 stacks. Bone meal can be used on any one of the saplings to make the tree grow more quickly. (Dark Oak must be planted similarly, but they don't grow tall enough to require the special harvesting techniques.)