I had that happen when trying to break up a 48" round of green doug fir. Used every wedge and they were getting lost in the wood. What to do? I went back and got another mega wedge. Got some help to flip the round and attacked it from the other side in the same location. It finally gave way. After that I let the rest of the rounds dry out more for a few months, then hired a couple eager HS football team jocks that were friends with my son. They wailed on those rounds like they were mortal enemies. Got the job done in a good day of splitting.