Degradation state and preservation quality of archaeological bamboo from a 2000-year-old Chinese royal tomb

This study presents an analysis of the anatomical structure of the archaeological bamboo, complemented by an examination of its chemical composition, structural characteristics, cellulose crystallinity, and thermal stability. The degraded fibre cell walls exhibited distinct porosity, indicative of the loss of secondary cell wall substances. Partial separation of the secondary wall layers from the middle lamella was observed in certain cell types. The results revealed a predictable diminution in hemicellulose and cellulose content, contrasted by an augmentation in relative lignin and ash content. The cellulose content and cellulose crystallinity index of archaeological bamboo were sharply reduced to 7.2% and 8.2%, respectively. Prolonged entombment had resulted in the predominant degradation of cellulose and hemicellulose in the unearthed bamboo, while lignin had remained relatively stable. At the same maximum water content (MWC), the bamboo underwent more severe degradation of carbohydrates, including the crystalline cellulose. These findings underscored the importance of understanding the degradation processes of bamboo, especially the changes in its chemical properties, in order to accurately assess its preservation state.