Tree Bark

Giovanni Ciotti

The outer bark (or more precisely the cork) of birch trees (Betula utilis, etc.) was virtually used anywhere the plants naturally grow (for the use of the inner bark of certain trees, see Bast paper). It was used alongside palm leaves in India, in particular in the historical region of greater Gandhara (from at least the 2nd c. BCE), but also in Nepal, Central Asia (where it was, however, most probably imported) and Mongolia (Ciotti 2021). Usually, the outer part of the bark is peeled from a tree, dried, smoothed with oil and polished. Finally, sheets are cut to the desired size to produce either scrolls, pothis or codices that are written with liquid black or coloured inks.

The use of birch bark is also well attested in Early Rus' between the eleventh and fifteenth century, when sheets of bark (see Folio) were rolled after having been written by incising the surface (then left uninked) and only extremely rarely by using liquid ink (Mendoza 2017, 147). The same material may also have been used in Finnish Karelia, but no material evidence is available (Haavio 1964, 46). Furthermore, birch bark was used in North America in the form of the so-called Ojibway scrolls, in which various kinds of drawings are incised and then blackened (Dewdney 1975).

The outer bark of the Agarwood tree or Eaglewood tree (Aquilaria malaccensis) has been used instead in other regions of Asia, in particular in Tai Ahom’s Assam (India) for pothis and in Batak’s Sumatra (Indonesia) for concertinas. The preparation process in Assam consists of several steps: various cycles of drying and boiling, rubbing with a paste of Mung bean (Phaseolus radiatus) and colouring with arsenic sulfide and/or mercury sulfide (vermillion) (Goswamee 2006, 75–76). In Sumatra the outer bark is dried, its edges cut straight, its surface evened, smoothed and polished with the leaves of trees such as the Ficus ampelas (Zollo 2020, 66).

Relevant analytic methods include:

DNA analysis and proteomics to identify the species,
Microscopy to visualise the structure of the surface and the cells, which can also be used for species identification (Teygeler and Porck 1995),
C¹⁴ for dating (Southon 2022),
X-Ray emission and vibrational spectroscopic techniques for the identification of additional materials on the surface.

References

Ciotti, G. (2021), ‘Notes for an ontological approach within manuscript studies: Object oriented ontology and the pothi manuscript culture’, in J. B. Quenzer (ed.), Exploring Written Artefacts: Objects, Methods, and Concepts, Berlin/Boston: De Gruyter, 865–888 <https://doi.org/10.1515/9783110753301-042>.
Dewdney, S. H. (1975), The Sacred Scrolls of the Southern Ojibway, Toronto: University of Toronto Press.
Goswamee, B. (2006), ‘Traditional method of sāñcīpat making and preparation of ink in ancient Assam’, in A. Sah (ed.), Indigenous Methods and Manuscript Preservation, New Delhi: National Mission for Manuscripts, 73–204.
Haavio, M. (1964), ‘The oldest source of Finnish mythology: Birchbark letter No. 292’, Journal of the Folklore Institute, 1/1–2: 45–66 <https://doi.org/10.2307/3814030>.
Mendoza, I. (2017), ‘The Novgorod birch-bark manuscripts’, manuscript cultures, 10: 145–159.
Southon, J. (2022), ‘C¹⁴, radio carbon dating, William's birch bark manuscript’, <https://doi.org/10.5683/SP3/IKMI1Q>.
Teygeler, R. and H. Porck (1995), ‘Technical analysis and conservation of a bark manuscript in the Dutch Royal Library.” The Paper Conservator, 19/1: 55–62 <https://doi.org/10.1080/03094227.1995.9638413>.
Zollo, R. (2020), ‘Der Inhalt der Batak-Schriftartefakte in der Ausstellung / The Content of the Batak Written Artefacts in the Exhibition’, J. van der Putten and R. Zollo (eds), Die Macht der Schrift: Die Manuskriptkultur der Toba-Batak aus Nord-Sumatra / The Power of Writing: The Manuscript Culture of the Toba Batak from North Sumatra, manuscript cultures, 14.