Composition of Nonpolar Extractives in Bark of Norway Spruce and Scots Pine

Abstract

Abstract The composition of nonvolatile extractives soluble in petroleum ether was investigated separately for inner and outer bark of Norway spruce (Picea abies (L.) Karst) and Scots Pine (Pinus silvestris (L.)). The bark extractives of one spruce and one pine tree were prefractionated by thin-layer chromatography and the detailed composition of free and esterified fatty acids, free and esterified sterols, triterpenoid alcohols and fatty alcohols, resin acids and diterpene aldehydes was determined by gas chromatography. Bark of four other trees was analysed by a routine method based on direct gas chromatography of the extracts. Fatty acids, resin acids and sterols accounted for ca 80% of extractives in inner bark and for 50% in outer bark. Qualitative differences between the extractives in inner and outer bark were noticed. The total amount of fatty and resin acids was about 1.54 of spruce and pine bark dry weight and the amount of sterols was 0.2–0.5%. These levels are low considering possible technical...