I remember back in the day we'd roll up newspapers into starter logs for the fireplace. They worked good, but lotsa ash.
Packing chips into tubes sounds like more practice in how wood heats twice, three times...
If you could figure out how to burn sawdust effectively you would have something.Henry Ford did it by inventing charcoal briquettes,true story.
Old Henry didn't waste anything ,in a way he kind of turned water into wine or lead into gold in his own way.
One old sawmill owner once said that sawdust costs the most to make and is worth the least money.
On the subject,there is a large mill locally.Hoge lumber of New Knoxville Ohio,the largest supplier of bowling alley maple in the world.They burn all their scrap ,sawdust and all to supply power for the mill,via a steam turbine generater.