Cleaving (riving) is used to turn a log into lumber or billets (short or thick pieces of wood) into firewood.
The work of using the axe, and its ability to split cleanly, depends on having flat sides with the minimum of friction, rather than all the force of the timber being concentrated on one protruding line.
Segments are halved symmetrically at each step, as this encourages them to split more evenly than attempting to cleave off thin sheets repeatedly from one end.
The ability to use several tools at once makes the use of an axe and wedges capable of cleaving far heavier logs than a froe.
The froe does however have a wider blade, and so may give a more precisely flat surface when cleaving wide timber, such as for roofing shingles.
They have small heads in terms of edge length, but are heavy as they are especially wide across the cheeks and have a steep taper for rapid splitting.
To split longer logs, wedges are driven with the heavy poll of this maul, giving its alternative name of "hammer-poll axe".