In a picture cavities from 2 to 7 microns in size in tracheids – cells of spruce wood are visible. At pyrolysis the structure of the carrying-out wood fabrics therefore in the formed charcoal there is a large number of the capillaries and a time possessing a big total surface that promotes its big adsorptive ability remains. At a usual temperature charcoal can adsorb various substances from their solutions, and also various gases, including inert.