Isn't birch technically a hardwood? Not up there with oak or chestnut, I know, but still better than most conifers.

Yes, burning as much of the wood gases as possible seems to be the way to go. Pricey, but as a long term investment pretty good, and as long as you've got enough coppice or willow in rotation it could potentially see you through the end of the oil age.

Dependent on global supply chains and unsustainable drinking habits, but I found this guy's technique of making briquettes from wood shavings, sawdust and coffee grounds quite impressive:





Could work without the coffee if the mix is right. Not a scalable solution unless there's a huge increase in woodworking and tree planting. Still, the kind of innovative approach that makes me feel there could be a way through the bottleneck.

cheers,
I