Collaborating with the British Museum
November 16, 2011
Samples of birch bark from Stone Lane Gardens are helping to build links with the past. At the end of October, Paul Bartlett travelled to the British Museum in London to hand over bark samples for analysis. Read on to find out more about this fascinating project:
This all began when Stone Lane Gardens was contacted by Dr. Pauline Burger, an Analytical Chemist from the Department of Conservation and Scientific Research at the British Museum. She was requesting bark samples of two species of birch; Betula lenta (the cherry birch from North America) and Betula pendula (our own native silver birch). The British Museum is carrying out a project to analyse the molecular structure of tars and pitches made from the distillation of many different tree barks, in the hope of being able to create a database of ‘molecular fingerprints’ that will help with identification of the tars and pitches used in the construction of ancient artefacts and structures.
We were delighted to be involved in such an interesting and important project, as it highlights the importance of preserving National Collections of plants. For some species it would be very difficult and costly to obtain such material in the wild. But having a National Collection on your doorstep means easy access to all that research material. A potential ‘gold mine’ of data waiting to be unlocked by UK scientists.
‘Dr. Burger works in a laboratory situated beneath the public areas of the museum. She creates tar in a furnace and then uses a process called GCMS (Gas Chromatography Mass Spectrometry). This involves heating up the sample (obtained by solvent extraction of the initial tar or pitch) so that the molecules are volatized and separated. The molecules are then hit by electrons and fragmented to obtain specific molecular fingerprint for every single molecule. The process is a lot more complicated than that, but that was as much as I could grasp!
As part of her research, Dr Burger has uncovered a lot of data about ancient uses of birch bark tar, and passed me a lot of information stemming from previous scientific research. One of the aims of Stone Lane Gardens is to increase our knowledge of Birch and to share that knowledge. An important part of this aim is the intended creation of an on-line database. This database will contain as much information on ‘Birch uses’ as we can collect. My wish is that Stone Lane Gardens becomes a centre of expertise for all things ‘Birch’ related. Our new website will enable me to begin collating and sharing that knowledge.
After my time at the British Museum, I headed for the British Library; only a short walk from the Museum. During my own research into Birch uses I had come across references to some ancient scrolls found in Afghanistan that were made of birch bark. These are known as the British Library Kharosthi Manuscripts; more commonly called the Gandharan Scrolls.
The British Library acquired these fragments of bark in 1994 and they are thought to be the oldest surviving Buddhist texts. They were found in clay pots, rolled in bundles. After painstaking unrolling, the fragments are now preserved between glass sheets in a protective environment. Not surprisingly I was not allowed to view the actual scrolls, but the Library does have a copy of a book describing the scrolls and I was able to read about the scrolls and see photos of them. I took photocopies to bring back to Stone Lane Gardens for our records. The Scrolls are thought to be from the early 1st century to the mid 2nd century AD. Birch bark was commonly used for writing paper during this period and in fact was still in use much later than this. Many birch bark scrolls have been found by archaeologists in the past, but only two are known to have survived in the West, though there are thought to be some in China and Nepal. Obviously their incredibly delicate nature makes them vulnerable to damage and decay, hence their rarity today’.
Paul Bartlett
Garden Manager