Oak wood degradation processes induced by the burial environment in the archaeological site of Biskupin (Poland)

Jeannette Jacqueline Lucejko,Leszek Babiński,Diego Tamburini,Francesca Modugno,Maria Perla Colombini,Magdalena Zborowska

doi:10.1186/s40494-020-00390-3

Abstract

The open-air Archaeological Museum in Biskupin (Poland) preserves and shows to the public a prehistoric settlement of Lusatian culture dating back to Early Iron Age (eighth century BC). The monitoring of the environment and dynamics of the wood degradation in the burial conditions at the site is fundamental for the in situ preservation of archaeological wooden materials. A monitoring program thus started in 2003 at the Biskupin site, using contemporary sound oak wood that was placed in two wet burial environments, characterised by different conditions. A multi-analytical protocol was exploited to obtain information on the structural, physical and chemical conditions of the buried wood. The study involved the application of gravimetric and wet chemical analysis, and instrumental techniques, including infrared spectroscopy (FTIR) and analytical pyrolysis (Py–GC/MS) to evaluate alterations in the buried oak wood over a 10-year period. The results showed that, during the burial period in both monitoring stations, there was only limited chemical transformation of the polysaccharide component, mostly involving hemicelluloses. The differences observed might be due to the natural compositional variability and inhomogeneity of oak wood. The final condition of the wood was very similar in the two burial environments. It is therefore suggested that the wet burial conditions in the Biskupin site represent a safe conservation environment for the in situ preservation of the wood remains, at least those presenting a good initial preservation state. This supports the conservation strategy adopted in the Biskupin Museum site.

Highlights

Excavating and conserving archaeological remains is not the only possible approach for their preservation
For what concerns the preservation of waterlogged wooden archaeological artefacts, one of the best known examples of in situ preservation is the archaeological site of Biskupin (Poland), where the wooden remains of a settlement of Lusatian culture dating back to the Early Iron Age are preserved [5]
The increase in wood porosity is directly related to the slight increase in the maximum water content (MWC) and to the slight decrease in the basic density (BD) (Fig. 1)

Summary

Introduction

Excavating and conserving archaeological remains is not the only possible approach for their preservation. In situ preservation is an increasingly common alternative [1,2,3]. In situ preservation of archaeological remains requires a regular monitoring of the conditions of the buried material, as well as the limitation and/or reduction of the impact and risk caused by the burial conditions. For what concerns the preservation of waterlogged wooden archaeological artefacts, one of the best known examples of in situ preservation is the archaeological site of Biskupin (Poland), where the wooden remains of a settlement of Lusatian culture dating back to the Early Iron Age (eighth century BC) are preserved [5].

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Results

Conclusion