Bark looks more like White or Green Ash instead of Silver Maple. Stubborn splitting I'd imagine,just like that Ash I brought home on Tuesday,glad that's done now!
I am not sure if that is Ash in your truck, but I have always found White Ash to split easy. Nice straight grain. Are we talking about the same stuff Thistle?
Could be.What little White Ash I've split was not too bad,while lots of the Green was more stubborn with spiral and/or twisted grain,even the knot free rounds.Can also be where it grows too,anything in yards or fence lines/underneath powerlines tends to be tougher than that grows in forest closer together.
That looks like some big boxelder I've had here at my place. Maybe it's not, but I bet you're right it's in that maple family.
Hey neighbour. I've always had the theory that knotted and gnarly wood is tougher to dry, but burns longer because the grain is tighter. I could be full of it though, Either way good BTU's.