Abstract: A saw tooth, of which a number are removably mounted on a tree-felling saw head, includes a body portion having a lead cutter and a trailing primary cutter separated by a throat. The combined lead cutters function to cut a narrow side wall kerf on each side of a larger principal kerf together with corresponding inside corners of the larger kerf. The remainder of the larger kerf is then cut out by the following primary cutters, forming a square cut end. As the cut progresses, the combined primary cutters separate the longitudinal fibers of the tree at the square cut end without double cutting the fibers, thereby improving cutting efficiency and reducing energy requirements in felling a tree.