the outer part of the birch cortex, consisting of easily separated, thin, semitransparent, smooth, white, yellowish, or reddish layers.
The best birch bark is obtained from trunks with a diameter of 20 cm and larger. Such products as tar are obtained by the dry distillation method, and bast boxes, baskets, and dishes are manufactured from birch bark. In ancient times, before the invention of paper, official documents and letters were written on birch bark.