Wood burning stoves
If my memory again serves me well, to drive out the tars and oils from wood requires heating to several hundred degrees. When done in an oxygen free atmosphere the end result is torified wood, which does not re-absorb moisture.
@derek-m, forget memory, you're already past my original knowledge.
I followed up what you mentioned and you're quite right. It seems the process drives off volatiles and reduces the calorific content by about 10% whilst producing a hydrophobic and stable fuel source. Or dimensionally stable material for guitars, but that's another story....
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and inverter
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solim profundum variat"