There was a time in our nation's history when times were so difficult that people were advised on how they could use wood in place of flour to bake their bread. This actual procedure was first shared through The Emigrant's Handbook (1848).
Chop fresh (green) beech tree wood into shaving sized pieces. You may substitute other turpentine free wood for the beech tree if you like.
Boil the beech shavings three or four times, stirring as they boil. This will take a strong hand to do as wet wood shavings are very heavy. Don't make too big a batch at a time unless you have a muscular helper.
Dry the shavings out. Laying them out flat on a clean surface in the sun is likely the most appropriate way of doing this. Using a cheesecloth or clean white linen would be preferable as you will need to pick them up once dry and they will crumble up.
Work them around with a firm hand to reduce the wood shavings into a powder, if possible. If you can't get them into powder form, at least break them up as best you can.
Bake the wood powder/crumbs in your oven 3 or 4 times using a large cookie sheet. The guide does not specify at what degree you would use. Remember, this was in 1848! I would suggest using a very low temperature. You are just encouraging the moisture to become completely evaporated from the wood at this stage.
Grind the wood powder/crumbs as you would grind corn. This will take on the same smell as corn flour at this point. It is reputed that it also tastes like corn flour. No leaven is required to prevent fermentation but you can use corn flour leaven if you wish.
Use your new wood flour to bake your bread. This wood flour is said to produce a spongy bread and "when much baked with a hard crust, is by no means unpalatable."