Selected physical parameters to characterize the state of preservation of waterlogged archaeological wood: a practical guide for their determination

Non-destructive and destructive methods for determining the physical parameters of waterlogged wood such as the porosity, the water content, the wet and dry bulk densities plus the density of the cell wall material are presented. Considerations in respect to determination of masses, volumes and sampling size are discussed.The influence of the density increment of the water, sorbed to the cell wall material, is discussed and introduced by a model for the constituents of waterlogged wood including volumes and masses of the cell wall material, the free water in the pores/cell lumen and the sorbed water in the cell wall.The density increment is introduced, as a correction factor in the equations for determination of the physical parameters. If the equations are used without the correction factor they are similar to the most frequently used methods for determining physical parameters of waterlogged wood. By including the correction factor and thereby incorporating the increased density of the sorbed water in the calculations, the presented equations make it possible to correctly determine values for the physical parameters of waterlogged archaeological wood.