First, huh? Why would the density of the wood change how much volume of wood is in the stack? If a stack of wood is 128 cubic feet, the amount of airspace is only affected by the tightness of the stacking job and the size of the pieces. Second, I thought you were right about the split smaller can be stacked tighter thing, but it's not true. You can fit more wood in the truck (or any stack for that matter) if it's in rounds than if it's in splits. Once you split a piece of wood there's no way you can stack it tighter than it was when it grew. Bigger pieces equals less air.