Cordwood Construction uses shorter logs, 18" cedar in this case, laid perpendicular to the wall and mortared, similar to a stone wall.
In this photo, you can see a cross section of a wall as it goes up. To the outside and inside of the wall there is a 5" strip of mortar, and in the centre of the wall is a mixture of sawdust and lime, which acts as insulation and a thermal break.
