Out doing a removal of a 30" dbh maple. Dropped the spar, bucked it up and went to roll the pieces out of the way for the stump cut. Buddy was helping me roll the first piece, I was on the end and he had the side with the next piece. As we started rolling it the piece beside ours shifted and, out of reaction I guess, he moved his hand to stop it (can't remember doing it). Next thing we know his hand is between the two pieces so I push with all I have on the one I am on and our other worker gets on the other piece pushing. We get him out and the words "holy S@#T" come out of his mouth. It ends up he had a wedding ring on and it crushed into his finger, through skin. With pliers he got it off and took him to the ER. End result he kept his finger but can't feel all too much in it, it hurts randomly, and is about 10 deg colder then the rest of his hand. Had he not had the ring on it would have broken but had less nerve and circulation damage.