I burned a lot of tulip poplar early last winter. It was ok to burn. It burns quite hot and got my stove up to temp very quickly, which was nice...however, every 3-4 hours I was having to reload. Also, it left behind large chunks of coal which took FOREVER to burn down. After a couple days of burning, I'd either have to spend a good part of the day sitting by the stove with the door open trying to burn down the coals, or throw out a large portion of the coals to make room for more wood. The good thing about the coals though, is even though the burn time of the wood was short, the coal would last all night making it easy to restart the fire the next morning.
By chance have you ever tried piling your un burnt coals/chunks up front and placing a single small split on top. Close your loading door and open the primary air all the way and let it burn vigorously/completely? I do this occasionally to reduce coal buildup. Works very well for me. Even this morning. Curious.
I do all of that, except the closing of the loading door part. I leave the door ajar to let even more air in. Maybe it burns down quick by closing the door?
Try closing the door and retaining all the heat. All I can say is it works for me! I do give it time to completely burn down. Somedays a hour or two.
The clearest difference to me between the two is wood color and cutting difference. Poplar bark Dead poplar wood Ash bark ash wood