Longer total burn time by cutting pieces shorter???

[Ronie]

At one time I had a Fisher Mamma Bear stove and built a small shelf that made it so the smoke had to travel to toward the front of the stove instead of going straight out the stove pipe in the back and it increased the burn time. I also did the same to an Ashley Wonderwood, a much longer shelf, with the same result. As far as using shorter pieces, I think it's a good idea if your around to feed it.

 

[ApePilot]

IMO the best way increase burn time is to decrease the surface area of the fuel. That is to say that you want the largest amount of wood you can get in the stove with the fewest number of pieces. You have observed this with the rounds. I find the longest burning fires are when I put two large pieces on a bed of coals and keep the draft low. By large I’m talking not being able to fit a third piece....

Exactly.
And.... starve the fuel combustion of oxygen. Keep it glowing rather than flaming. The more flames, the more BTUs are being pumped up the chimney and less being radiated into your house.
A given log will have the same BTUs no matter how you burn it, but your obvious goal is to keep as many BTUs radiating into your house rather than up the chimney. So, keep the logs BIG and the oxygen small and that log will burn for a longer period of time, and will radiate a larger percentage of it's limited energy into your house.