The following paper presents the results of the examination of archaeological wood from excavations carried out in the gardens of Wilanów Palace. The main purpose of the research work was to determine its state of preservation. In order to accomplish this, chemical and physical examinations were carried out on wood samples taken from the level of the grotto foundations.
The article presents results of the research on the shrinkage of slightly degraded, freeze-dried archaeological oak-wood (Quercus sp.). Before drying, samples of wood were treated with 10, 20, and 30% water solutions of PEG 300, PEG 4000, and sucrose, as well as the mixture of both polyglycols. Dimensional changes in tangential, radial, and longitudinal directions were determined immediately after freeze-drying, and then, after seasoning of the freeze-dried samples in the air at RH 44 and 70%. Shrinkage of untreated and treated freeze-dried oak-wood was considerably smaller, than that of the material, which was dried naturally (ASET from 49 to 97%, ASER from 39 to 98%).
Changes of physical and chemical properties, mass loss and susceptibility of oak wood to decay caused by Basidiomycetes fungi were assessed after wood samples had been taken out of the sea within the framework of MACHU project. Test samples of oak wood of the dimensions of 250 × 10 × 10 mm were placed in coastal waters of the Baltic Sea at the area of medieval seaport in Puck and in waters of the Gdansk Bay at the same longitude as Orłowo (near the wreck of Swedish warship Solen). The samples taken out of the sea were examined visually and described. Changes in mass of the samples, their bending strength and modulus of elasticity, compression strength along the grain, ability to decay caused by Trametes versicolor fungus, content of mineral substances and substances soluble in water, ethanol-benzene mixture and in 1-percent aqueous solution of NaOH, content of cellulose, lignin and pentosanes as well as pH of the wood were investigated. The properties of samples taken out of the sea after 6 months of immersion were compared with the properties of control twin samples of oak wood which had not been immersed. The results obtained so far indicate that noticeable, measurable changes in oak wood immersed in sea occur already in half a year since immersion, so observation of them may be useful for protection and monitoring of underwater archaeological objects.
The article presents changes in the dimensions of well-preserved, waterlogged archaeological oak and pine wood, untreated and treated with PEG 300, after drying in the air and in vacuum conditions. The effectiveness of wood conservation was evaluated on the basis of wood shrinkages in tangential and radial directions, cross-section shrinkages and anti-shrink efficiencies (ASE). The changes in the dimensions of the oak wood samples treated with a 25% solution of PEG 300 and dried in vacuum conditions were distinctly lower than the results obtained after the drying of the wood in the air. The shrinkage in the treated and vacuum-dried pine wood was lower than the shrinkage in the oak wood, but it did not differ much from the results obtained in the case of the treated wood, dried in the air.