Fell a tree and walk up to the trunk where it lies: it is solid now. Swing the axe where you want it cut, starting near the thick end. A V opens a little with every blow until a round drops off onto the ground, as thick as the trunk itself.
Swing at the round where it lies and it splits and falls open, halves side by side with their fresh faces up, then quarters, until the pieces are firewood billets lying right there, as much wood as the round weighed. A blow aimed at a bigger piece beside a billet goes to the bigger piece: the axe looks through a billet.
Look at a billet and press E: it goes into your pack as wood, counted by its weight. Carry it to your fire and Shift+R puts it on, and the fire holds and burns it by its weight.
