At times of severe famine in Finland late 1500-1600, the bread flour was extended with the use of wheat chaff, straw and the inner layer of pine tree bark. The ratio would usually start at about 10:1 (flour: bark meal).
The harvesting was done in the springtime, the method of harvesting was done by making a vertical cut on the tree bark, then cutting a line across the top, and the bottom. The tree bark would then be gently levered open until access to the 2mm thick white flesh of the inner tree bark was made. Then it was removed and the tree bark returned to the original position. I guess it was tied tight with some string, to ensure that the tree bark grew back tight against the tree trunk and protected it. If not then it would almost be like “ring barking (360′)” a tree, meaning a slow death of the tree.
The inner layer of the bark was dried and later milled as bread flour.
The bread bark meal has a high mineral content in the following; zinc, magnesium, calcium, and iron.
Also contains vitamins and high in fiber, the energy content is very low. The “Pettu” bread is still made in some places for historic and tourism purpose. One such place is the Kilen Museum.
http://sydaby.eget.net/swe/kindex.htm
Another such place where the bread can be purchased is at the Salla War Museum. When I visited the War Museum at Salla in 2011, I did actually purchase some “Pettu” bread. This particular bread was made into thin crisp bread 20cm disks. The bread package contained some 20 rounds of crisp Pettu bread. There were a slight aroma and flavor of a pine tree, other than that it was like eating regular crackers with a cheese plate, the cost was about 5€ per package.
It was a novelty experience tasting and eating “Pettu” bread, knowing that in the severe famines of late 1500-1600.
Many improvisations were made at that time to extend food ingredients to save lives and to avoid hunger. Despite the improvisations and food extensions many thousands of people died of starvation.
For more information on the Salla Museum click on the link below.