Microstructural and Chemical Characteristics of Archaeological White Elm (Ulmus laevis P.) and Poplar (Populus spp.)

The degradation states of archaeological white elm, with an age estimation of ~350 years, and poplar, with an age approximation of ~1000–1200 years, were studied by means of different chemical and microscopy analyses. Recently cut samples from the respective species were used for comparison reasons. The chemical composition analysis of the archaeological samples showed significantly low holocellulose values, while the lignin, extractive, and ash contents were considerably high, as compared with the recently cut samples. The Fourier-transform infrared (FTIR) spectroscopy also confirmed the changes in the chemical structure of the archaeological elm and poplar samples. The light and scanning electron microscopies illustrated that the erosion bacteria were the main degrading agent in both archaeological elm and poplar, although the hyphae of rot fungi were detected inside the vessel elements of the archaeological poplar sample.