Will it has been my experience... standing-dead elm has always been noticeably harder and denser (heavier) than any cut green. Just my opinion, but I believe it's the way the stuff shrinks-up when standing with the bark on... I think gravity pushes the water down and out through the roots, and with the bark still on it the wood is sealed and has no choice but to shrink and compress. Eventually that releases the bark and it falls away. It may not change the overall BTU's (per pound) in the wood, but it sure in hell improves the burning and coaling properties of it.
There's a bit of a trick to know when to cut it... pretty much just after most of the bark falls, signalling the wood has shrunk up tight, dense and hard. Cut it too soon and it will still be sort'a "green" and won't shrink-up the same. Wait too long and it gets a bit punky, especially in the base and round the crotches. It easy to tell if you caught it at the perfect time... smack two splits together and they'll make a high-pitch ringing sound, almost metallic-like. I've never heard that sound from any elm cut green, ya' just get a wooden thud-like sound, even after sittin' split in stacks for a couple years.
*