I need to repair a log cabin for a regular customer, water damage has rotted out the logs that make up an outside corner of the building.

These logs are huge, some as large as 24" in diameter. I have got the new ones from West Virginia and they are on site waiting for spring like I am.

Any tip to get these logs out? I am well aware of how to brace the structure while the repair goes on, but cutting the old logs out is my only question.

Would a mortiser be the best tool? Then finish off with a chainsaw? I could also use some advice on cutting the scribes for the overlapped corners.

I'm not sure how to attach pictures or I would put a few up to show what exactly I am looking at.