Birch bark tar (sometimes referred to as birch bark pitch) is a substance that is synthesized by dry distillation of birch tree bark.

Birch bark pitch made in a single pot: The birch bark is heated under airtight conditions, the final product consists of tar and the ashes of the bark.
Modern way of producing birch bark tar in a single pot: the birch bark is heated under airtight conditions; the final product consists of tar and the ashes of the bark.

Chemical composition

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Birch bark tar is mainly composed of triterpenoid compounds of the lupane and oleanane family, which can be used as biomarkers to identify birch bark tar in the archaeological record. The most characteristic molecules are betulin and lupeol, which are also present in birch bark.[1][2] Some of these molecules degrade into other lupane and oleanane skeleton triperpenes. The most commonly found additional molecules are lupenone, betulone, lupa-2,20(29)-dien-28-ol, lupa-2,20(29)-diene and allobetulin.[3][4][5]

Ancient and modern uses

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Birch bark tar use as an adhesive began in the Middle Paleolithic. Neanderthals produced tar through dry distillation of birch bark as early as 200,000 years ago.[6] A 2019 study demonstrated that birch bark tar production can be a simpler, more discoverable process by directly burning birch bark under overhanging stone surfaces in open-air conditions.[7] However, at Königsaue (Germany), Neanderthals did not make tar with this method but rather employed a technically more demanding underground production method.[8] A find from the Dutch North Sea[9] and two tools from the Italian site Campitello show that Neanderthals used birch bark tar as a backing on small 'domestic' stone tools.

Birch bark tar also has been used as a disinfectant, in leather dressing, and in medicine.[citation needed]

A piece of 5,000-year-old chewing gum made from birch bark tar, and still bearing tooth imprints, was found in Kierikki, Finland.[10] Genetic material left in the gum enabled novel research to identify population movements, types of food consumed, and types of oral bacteria found on their teeth.[11]

A different chewing gum sample, dated to 5,700 years old, was found in southern Denmark. A complete human genome and oral microbiome was sequenced from chewed birch bark tar. Researchers identified that the individual who chewed the gum was a female who was closely related genetically to hunter-gatherers from mainland Europe.[12]

Fletching on arrows were fastened with birch bark tar, and rawhide lashing and birch bark tar were used to fix axe blades in the Mesolithic period.

Birch bark tar was more frequently discovered in archaeological contexts dating from the Neolithic to the Iron Age. For example, birch bark tar was identified to serve as an adhesive to repair[13][14][15][16] and decorate/paint ceramic vessels,[17] as a sealing/waterproofing agent.[18][19] A well-known example of birch bark tar hafting during the copper age is Ötzi’s hafted arrow points and copper axe.[20] Multiple discoveries show that birch bark tar was also used to assemble metal artefacts, such as pendants and other ornaments, on both a functional and decorative level.[21][22] During the Roman Era, birch bark tar is mostly replaced by wood tar,[23][24] but birch bark tar is still used, for example, to decorate hinges and other bone objects.[25]

Russia leather is a water-resistant leather, oiled with birch bark oil after tanning. This leather was a major export good from seventeenth- and eighteenth-century Russia, as the availability of birch bark oil limited its geographical production.[26] The oil impregnation also deterred insect attack and gave a distinctive and pleasant aroma that was seen as a mark of quality in leather.

Birch bark tar is also one of the components of Vishnevsky liniment.[27]

Birch bark tar oil is an effective repellent of gastropods.[28] The repellent effect lasts about two weeks.[28] The repellent effect of birch bark tar oil mixed with petroleum jelly and applied to a fence can last up to several months.[28]

Birch bark tar oil has strong antiseptic properties,[29] owing to a large amount of phenol derivatives and terpenoid derivatives.

Birch bark tar oil was used in the eighteenth century alongside civet and castoreum and many other aromatic substances to scent the fine Spanish leather Peau d'Espagne. At the turn of the twentieth century, birch bark tar had become a specialty fragrance material in perfumery as a base note to impart a leathery, smoky note in fragrances, especially from the leather and tobacco genre, and to a lesser extent in Chypres, especially Cuir de Russie perfumes and fragrance bases, typically together with castoreum and isobutyl quinoline. It is used as an ingredient in some soaps, i.e. the scent of Imperial Leather soap, though other tars (i.e. from pine, coal) with an equally phenolic and smoky odour are more commonly used in soaps as a medicating agent.

References

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  1. ^ Hayek, E.W.H., Jordis, U., Moche, W., Sauter, F., 1989. A bicentennial of betulin. Phytochemistry. 28, 2229–2242.
  2. ^ Hayek, E.W.H., Krenmayr, P., Lohninger, H., 1990. Identification of Archaeological and Recent Wood Tar Pitches Using Gas Chromatography/Mass Spectrometry and Pattern Recognition.
  3. ^ Aveling, E., Heron, C., 1998. Identification of Birch Bark Tar at the Mesolithic Site of Star Carr. Ancient Biomolecules. 2.
  4. ^ Regert, M., 2004. Investigating the history of prehistoric glues by gas chromatography-mass spectrometry. journal of separation science. 27, 244–254.
  5. ^ Rageot, M., 2015. Les substances naturelles en Méditerranée nord-occidentale (VIe-Ie Millénaire BCE) : chimie et archéologie des matériaux exploités pour leurs propriétés adhésives et hydrophobes (Doctorat). Université Nice Sophia Antipolis.
  6. ^ Kozowyk, P. R. B.; Soressi, M.; Pomstra, D.; Langejans, G. H. J. (2017-08-31). "Experimental methods for the Palaeolithic dry distillation of birch bark: implications for the origin and development of Neandertal adhesive technology". Scientific Reports. 7 (1): 8033. Bibcode:2017NatSR...7.8033K. doi:10.1038/s41598-017-08106-7. ISSN 2045-2322. PMC 5579016. PMID 28860591.
  7. ^ Schmidt, P.; Blessing, M.; Rageot, M.; Iovita, R.; Pfleging, J.; Nickel, K. G.; Righetti, L. & Tennie, C. (2019). "Birch tar extraction does not prove Neanderthal behavioral complexity". PNAS. 116 (36): 17707–17711. doi:10.1073/pnas.1911137116. PMC 6731756. PMID 31427508.
  8. ^ Schmidt, P.; Koch, T.; Blessing, M.; Karakostis, F.A.; Harvati, K.; Dresely, V. & Charrié-Duhaut, A. (2023). "Production method of the Königsaue birch tar documents cumulative culture in Neanderthals". Archaeological and Anthropological Sciences. 15 (6): 84. doi:10.1007/s12520-023-01789-2. PMC 10202989. PMID 37228449.
  9. ^ Niekus, Marcel J. L. Th.; Kozowyk, Paul R. B.; Langejans, Geeske H. J.; Ngan-Tillard, Dominique; van Keulen, Henk; van der Plicht, Johannes; Cohen, Kim M.; van Wingerden, Willy; van Os, Bertil; Smit, Bjørn I.; Amkreutz, Luc W. S. W. (2019-10-21). "Middle Paleolithic complex technology and a Neandertal tar-backed tool from the Dutch North Sea". Proceedings of the National Academy of Sciences. 116 (44): 22081–22087. Bibcode:2019PNAS..11622081N. doi:10.1073/pnas.1907828116. ISSN 0027-8424. PMC 6825292. PMID 31636186.
  10. ^ "Student dig unearths ancient gum, 2007". 20 August 2007.
  11. ^ Ancient gum DNA, Science, The New York Times, December 17, 2019
  12. ^ Jensen, Theis Z. T.; Niemann, Jonas; Iversen, Katrine Højholt; Fotakis, Anna K.; Gopalakrishnan, Shyam; Vågene, Åshild J.; Pedersen, Mikkel Winther; Sinding, Mikkel-Holger S.; Ellegaard, Martin R.; Allentoft, Morten E.; Lanigan, Liam T. (2019-12-17). "A 5700 year-old human genome and oral microbiome from chewed birch pitch". Nature Communications. 10 (1): 5520. Bibcode:2019NatCo..10.5520J. doi:10.1038/s41467-019-13549-9. ISSN 2041-1723. PMC 6917805. PMID 31848342.
  13. ^ Bosquet, D., Regert, M., DUBOIS, N., Jadin, I., 2001. Identification de brai de bouleau sur quatre vases du site rubané de Fexhe-le-Haut-Clocher «Podrî l’Cortri». Premiers résultats.
  14. ^ Urem-Kotsou, D., Mitkidou, S., Dimitrakoudi, E., Kokkinos, N., Ntinou, M., 2018. Following their tears: Production and use of plant exudates in the Neolithic of North Aegean and the Balkans. Quaternary International. 496, 68–79.
  15. ^ Urem-Kotsou, D., Stern, B., Heron, C., Kotsakis, K., 2002. Birch-bark tar at Neolithic Makriyalos, Greece. Antiquity. 76, 962–967.
  16. ^ Rageot, M., Lepère, C., Henry, A., Binder, D., Davtian, G., Filippi, J.-J., Fernandez, X., Guilaine, J., Jallet, F., Radi, G., Thirault, E., Terradas, X., Regert, M., 2021. Management systems of adhesive materials throughout the Neolithic in the North-West Mediterranean. Journal of Archaeological Science. 126, 105309.
  17. ^ Morandi, L.F., Porta, S.N., Ribechini, E., 2018. Evidence for Birch Bark Tar Use as an Adhesive and Decorative Element in Early Iron Age Central Italy: Technological and Socio-Economic Implications. Archaeometry. 60, 1077–1087.
  18. ^ Hayek, E.W.H., Krenmayr, P., Lohninger, H., 1990. Identification of Archaeological and Recent Wood Tar Pitches Using Gas Chromatography/Mass Spectrometry and Pattern Recognition.
  19. ^ Regert, M., Vacher, S., Moulherat, C., Decavallas, O., 2003. Adhesive Production and Pottery Function During the Iron Age at the Site of Grand Aunay (Sarthe, France)*. Archaeometry. 45, 101–120.
  20. ^ Sauter, F., Ulrich, J., Graf, A., Werther, W., Varmuza, K., 2000. Studies in organic archaeometry I: identification of the prehistoric adhesive used by "Tyrolean Icemen" to fix his weapons. Arkivoc. V, 735–747.
  21. ^ Regert, M., Rolando, C., 2002. Identification of Archaeological Adhesives Using Direct Inlet Electron Ionization Mass Spectrometry. Analytical chemistry. 74, 965–75.
  22. ^ Courel, B., Schaeffer, P., Féliu, C., Thomas, Y., Adam, P., 2018. Birch bark tar and jewellery: The case study of a necklace from the Iron Age (Eckwersheim, NE France). Journal of Archaeological Science: Reports. 20, 72–79.
  23. ^ Balsan, L., 1951. L’industrie de la résine dans les Causses et son extension dans l’empire romain. Gallia. 9, 53–55.
  24. ^ Trintignac, A., 2003. La production de poix dans la cité des gabales (Lozère) à l’époque gallo-romaine. RAP. n°1/2, 239–248.
  25. ^ Regert, M., Rodet-Belarbi, I., Mazuy, A., Dantec, G., Dessì, R.M., Henry, A., Rageot, M., Briz, S., 2019. Birch bark tar in the Roman world: the persistence of an ancient craft tradition. Antiquity. 93.
  26. ^ "Production of Russia Leather" (PDF). The Honourable Cordwainers' Company. 1807. Archived from the original (PDF) on 2016-03-04. Retrieved 2013-10-04.
  27. ^ Charman, C. (12 June 1999). "Vishnevsky liniment and ichthammol: on the perspectives of application in military medicine and other fields". The BMJ. 318 (7198): 1600–1604. doi:10.1136/bmj.318.7198.1600. PMC 1115970. PMID 10364122.
  28. ^ a b c Lindqvist, I.; Lindqvist, B.; Tiilikkala, K.; Hagner, M.; Penttinen, O.-P.; Pasanen, T.; Setälä, H. (2010). "Birch tar oil is an effective mollusc repellent: field and laboratory experiments using Arianta arbustorum (Gastropoda: Helicidae) and Arion lusitanicus (Gastropoda: Arionidae)". Agricultural and Food Science. 19 (1): 1–12. doi:10.2137/145960610791015050.
  29. ^ Wanamaker, L, "Birch Tar Oil A Powerful Antiseptic", OtzisPouch, 2020-04-01
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