Aging of wood under long-term storage in a salt environment

Aging of archeological wood in a salt environment was assessed in Hallstatt, Upper Austria, where Bronze Age wooden findings of the archeological salt mining site were compared with recent wood samples from the same site. Three species (Picea abies, Abies alba and Fagus sylvatica) were investigated. Recent samples covered all main geological units within the salt valley. FTIR spectroscopy was used to determine differences in wood chemistry. Principal component analysis was used to display the segregation of the data set according to the different factors and to give a measure of the strength of the effects. Results revealed that deacetylation processes took place at the wood material. The aging process affects wood chemistry significantly stronger than differences in earlywood and latewood. Together these two factors accounted for 80 % of data variability. As a third factor, the tree species segregated the data set. Geological differences in the sampling sites were not mirrored in the FTIR spectra.