Chapter 7. Evaluating the state of preservation of waterlogged archaeological wood prior to conservation (Contributo in volume (capitolo o saggio))

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Label
  • Chapter 7. Evaluating the state of preservation of waterlogged archaeological wood prior to conservation (Contributo in volume (capitolo o saggio)) (literal)
Anno
  • 2013-01-01T00:00:00+01:00 (literal)
Alternative label
  • Pizzo B., Macchioni N., Capretti C. (2013)
    Chapter 7. Evaluating the state of preservation of waterlogged archaeological wood prior to conservation
    Nova Science Publishers, Inc., New York (Stati Uniti d'America) in Cultural Heritage. Protection, Developments and International Perspectives. Focus on Civilizations and Cultures, 2013
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Pizzo B., Macchioni N., Capretti C. (literal)
Pagina inizio
  • 139 (literal)
Pagina fine
  • 171 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#titoloVolume
  • Cultural Heritage. Protection, Developments and International Perspectives. Focus on Civilizations and Cultures (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 32 (literal)
Note
  • Research gate (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • CNR-IVALSA, Sesto Fiorentino (literal)
Titolo
  • Chapter 7. Evaluating the state of preservation of waterlogged archaeological wood prior to conservation (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#isbn
  • 978-1-62808-812-0 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#curatoriVolume
  • P. Frediani, M. Frediani, L. Rosi (Eds.) (literal)
Abstract
  • to be largely utilized owing to its good mechanical and physical properties, to the easiness of its use and workability, as well as to its considerable availability and cheapness. Therefore, wood artefacts are an important issue to be taken into consideration in the modern approach to conservation of Cultural Heritage. Among the wooden objects deserving attention, waterlogged archaeological wood represents a highly interesting case. In fact, this material, being preserved under the water table and thus in conditions of almost complete anoxia, is altered only limitedly and in a manner which does not compromise the exterior integrity of the objects. However, waterlogged wood is attacked internally by microorganisms (bacteria and fungi), as well as environmental factors. These elements appreciably decay the wood tissue by changing both its cellular structure and its chemical and physical properties compared to non-degraded material. In fact, nearly always the altered material needs to be treated before it can be put on display in a museum (it mostly depends on the extent of decay), and the conservation procedure must be based on the correct evaluation of the state of preservation. This chapter reports on the characteristics of waterlogged archaeological wood decayed at various levels, analyzing a large number of samples of different wood species and burial times, coming from several archaeological excavations in Italy. The chapter also analyses how a correct diagnostic evaluation can be obtained only after an integrated multidisciplinary approach, making use of quantitative and reliable data. It is possible to carry out detailed evaluations through simple and broadly used techniques, which, however, have to be taken into consideration attentively before the state of preservation of the material can be established. For example, microscopy allows both to identify the timber used and to observe the anatomical structure present, thus enabling to recognize the decay agents and the parts of the cell walls degraded. Chemical analyses enable to quantify the depletion of structural polysaccharides caused by the decay process, as well as any other possible changes in the chemical structure of the wooden tissue. Physical characterization enables to evaluate the mass loss after decay and the increase in water content (i.e., porosity) present in the material. Furthermore, in order to attain consistent evaluations and establish how specific factors (such as the wood species) affect resistance against alteration, the various physical and chemical parameters need to be combined among each other so as to increase the readability and usefulness of the data. The \"effective\" chemical parameters can thus be used instead of the raw ones (directly coming from chemical measurements), enabling to refer to the presumed original mass of wood (i.e., before burial and therefore before any process of decay) rather than to the mass of degraded, ash-rich, archaeological material. This also allows for a direct comparison of data referring to materials even in highly different states of preservation. A correct diagnostic evaluation helps to understand the new properties of decayed wood and, in perspective, to classify the material according to its true level of decay. Analogously, a correct classification of the material can enable to tailor the treatment method on the basis of the decay class. This chapter is mainly oriented toward conservators, and in general toward those who are in charge of following and possibly setting up a conservation process, from retrieval to the phases leading to the actual treatment, in the attempt of giving the right importance to the preliminary diagnostic analysis. (literal)
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