It depends on if the tree was live or not...and if it was cut sap up, or down. And split size of course too...
Single row stack, on railroad rails and ties, concrete pipe casing or anything that will support the weight-Southern exposure means more total daylight and my prevailing wind is from the west so my stacks are aligned W to E-Totally exposed to elements for 6 mos, top covered for next 6 and to the shed-Air from underneath is sorely underrated….
We have very moist soil here, and stacking on skids helps, but the bottom row or 2 doesn't dry as well.
Now, I remember you are the guy with the railroad rails. Makes such awesome stacks! Looking at your stack and reading your comments, I can see how you could be right. With that much room below the stack, it's enough room that wind can readily get under there and that would create vortices around the entire stack. Hmmm... interesting. Have you hit upon the secret? Someone should do a PhD dissertation on fastest ways to cure wood! Hmmm... I wonder if two cinder blocks (concrete blocks) stacked atop one another every eight feet to support the runners would be stable. That is my setup on my best stacks, except it's only one cinder block supporting the runners, not two. Wonder if it would be stable or wobbly. Two would be about a foot tall.
That would be about 16" tall. I would put a 4" solid cap block on the ground, then 8" block on top, spaced about 4-5' apart for the most stable stacks.
Yawner, I use salvaged RR ties cut to 24” as my rack are for 16” splits single row-On edge, the RR tie is 9” high and the rails are @5”, it puts my stacks 13” off the ground so whatever you use for top rail would likely be at least 3” thick right? Cinder blocks not too stable, but if your ground is level it should be ok.