Shape recovery of collapsed archaeological wood ware with active alkali-urea treatment

Most wooden remains from archaeological sites in waterlogged burial environments are found to be intact without shrinkage despite centuries of storage. However, waterlogged wooden remains are subject to shrinkage damage and some even lose up to 80% of their original volume when exposed to air. The shrinkage of archaeological waterlogged wood with the loss of a large part of the initial volume of the wooden remains has been considered irreversible. Here we show that “active alkali-urea”, serving as a re-swelling chemical agent, can almost fully restore the collapsed archaeological wood to its original shape. The restoration experiment showed that the main reason for the restoration of collapsed wood is that the collapsed cell cavity almost completely recovered its original shape during active alkali-urea treatment. We suggest that the shape of collapsed archaeological wood remains can be fully recovered, and that the collapsed archaeological wood can thereby recover its valuable cultural properties.