Alterations in the anatomy and chemical structure of archaeological wood from a tomb of northern china due to different fungal rots

This paper aims to identify the decay types and investigate the chemical alterations in the three types of fungal decayed archaeological wood from Dongshan Han Tomb M6 (ca. 200-100 B.C.) in Taiyuan City, China. Microscopy, FT-IR, 13C NMR and XPS were adopted to reveal the features of the samples. The results show that from the microscopic and chemical perspectives, these samples are consistent with the characteristics of brown-rot, white-rot and soft-rot. However, all the samples show the accumulation of carboxylic acids or carboxylate salts from extensive oxidation of lignin, which were not observed in artificial fungal decayed wood. Moreover, different fungal decay types and pH values of the samples corresponding to the alternative forms of carboxylic acid or carboxylate salt are considered to be influenced by combined factors, such as the position in the tomb, groundwater level, moisture content, oxygen availability, etc. This study may provide a reference for the deterioration and conservation of fungal decayed wooden artifacts in the tomb of northern China where alkaline loess is the main soil type.

Short note: The impact of glue-lines on the protective effect of a low- pulsed electric field in wood

A wood protection method using electric fields to inhibit wood decay by brown rot fungi has been investigated in laboratory trials. Glued and non-glued wood samples were exposed to fungal attack for 6 weeks in Petri dishes and showed significantly reduced mass loss when connected to a low pulsed electric field (LPEF). The mass loss of LPEF-protected samples was in average lower than 10%, with a wood moisture content above 40%. The mass loss of untreated wood samples was above 30% in average. The glue line did not represent a barrier for the electric field in the test setup (a), where the glue line was applied on the transverse section of two glue-jointed wood sample halves. A test setup with two glue lines at the tangential side of three jointed wood samples, showed only slightly higher mass loss compared with wood samples consisting of two jointed halves. It is concluded that glue lines using the MUF glue mix used in this study do not impede the protective effect of LPEF.