MCI Project Summaries 2008 - Smithsonian Institution

MCI 6212 Investigation of Microorganisms and Composition of Archaeological
Wood Charcoal
MCI Staff: Magdalena Moskal, Robert J. Koestler, Mel J. Wachowiak, Judy Watson
During the analysis of wood charcoal remains from archaeological sites, it is common to
find different microorganisms present in the plant tissue. However, one may encounter
difficulties when attempting to identify these microorganisms and the time of their attack. The
biodeteriorated structure of wood and the fungi responsible for its decay exhibit similar
characteristics in both wood and charcoal samples. The factor of limited or unlimited oxygen
supply seems to have little influence on the preservation of fungi because in both kinds of
samples hyphae were documented as individual hypha, mass of mycelia or as hyphal imprints.
The pattern of decayed wood attacked by the three major wood-rot groups (white-rot, brown-rot,
and soft-rot) may be a valuable source of information when conducting a charcoal analysis. This
is because the preservation of altered wood structure is found in macrostructure of archaeological
charcoals as well as the ultrastructure of the wood. The results presented in this project show the
possibility of recognizing pre-burning microbial activity because of the preservation of both
fungal hyphae and wood deteriorated structures after burning. However, the identification of the
fungal agent still presents several problems due to the similar morphology of the fungi, the
analogous features of wood-decayed pattern, and the limited analytical techniques available to
study archaeological charcoals.
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