It took a long time to make an Ax or any other tool which would be able to complete the job. I doubt they would risk their tool by hitting it repeatedly with another tool like a wedge.
Natives of the Pacific Northwest Coast developed sophisticated woodworking technologies. In order to split redwood or western red cedar they used elk antler wedges in conjunction with stone mauls. They also used the wedges along with adzes and chopping tools (large cobble choppers) and in some areas celts (hand axes) to fell and shape large soft wood trees.
Edit: added maul link.