An analytical method has been developed for the assignment of recent and archaeological wood tar pitches to the species of trees used for their preparation. It incorporates the prepurification by Kugelrohr distillation and solid-phase extraction followed by gas chromatography/mass spectrometry analysis. Distribution patterns of volatile, thermostable triterpenoids, and steroids characterizing the biological origin of the pitches are evaluated by principal component analysis (PCA) and discriminant component analysis (DCA) of the data. Quantities of 10-100 mg of archaeological material can thus be characterized. By comparison with recent pitches of known origin, 14 archaeological samples have been identified as birch bark pitches. In addition, 28 substances present in recent barks and pitches could be identified. -- AATA