Got a log load delivered this Spring, I've just been chipping away at it in my spare time for a while now. Had a few large-ish (20" diameter or so) hickory logs in there. Found them a pain in the ass to split when fresh.. Stringy, and the bark was holding everything together too. Finished bucking up those logs, then let them sit for a while.. just went back to them this morning, and it was worlds easier. Still stringy-ish, but nothing like what it was, and the bark was a non-issue anymore, just breaking right off like oak bark.
TL; DR- if you're having a hard time splitting hickory, buck it up and let it sit for a few months. Way easier then.
TL; DR- if you're having a hard time splitting hickory, buck it up and let it sit for a few months. Way easier then.