I also don’t fret too much about covering my stacks, although I usually cover the stack I’m burning this winter, but never in the summer and next winter’s stack probably isn’t.
Birch (and some other woods) have bark that is completely waterproof. So in log form in doesn’t dry well, begins to rot, water is a product of the rotting, wood gets wetter,rots more and,.. Gone. Ash is more durable although still needs processing before too long, although at stove length it’ll dry.
Get some pallets and stack off the ground.
I’ll just say, fiskars x27. It’ll rattle through ash and birch much quicker then a hefty maul. I find birch I dream to split and often do it with my much smaller axes, x21 is plenty. You’ll find easy splitting wood is processed quicker by hand than with an electric splitter.