Abstract: A saw carrier assembly has a loop of saw chain and a powered sprocket to drive the saw chain. The assembly also has a saw chain journalling structure having a rotatable circular periphery cooperating with the saw chain to mount the chain to rotate therewith to reduce friction and to resist sawing forces. The saw journalling structure and sprocket cooperate with a saw support structure so that the chain saw extends as a loop around the sprocket and journalling structure. The journalling structure has a thickness less than the kerf produced by the saw to permit a portion of the saw journalling structure to pass into the kerf with negligible interference therewith. This enables a tree to be cut using a saw journalling structure of slightly less diameter than diameter of the tree where it is cut, and reduces frictional losses normally associated with a fixed chain saw support bar.