Mediante fact, summer sultriness is particularly high during August in South Italy
As referred con the retroterra section, the carefully sopra situ observation of the Altar Machine allowed detect several damages on the wood elements like cracks, deformations, surface detachments and scratches, dust layers, colour modifications, and many holes caused by the insects. Wood deterioration was due to the manufacturing process, esatto the Altar Machine usage, and sicuro the microclimate per the apsidal distretto of the church. The numerous galleries produced by the xylophagous insects weakened the wood, making the substitution of elements or the introduction of plugs necessary.
The identification of the wood species was undertaken because the diagnosis of the botanical species represents per great importance con the technological and historical artistic study of a wooden artefact paio esatto possible implications relating puro the conservation. Con fact, every species exhibits peculiar characteristics that delineate the physical, mechanical and durability properties of the material as features of the xylem of the tree botanical species.
The species identification allowed sicuro find six different kinds of wood that were used sopra relation to the technological characteristics of the altar elements. The results are summarized sopra Table 3.
The wood species used for the Machine elements could be easily found on the territory of Gangi. The availability and the cost of timber influenced the choice of the wood by local artisans . The presence of Picea abies Karst per the tabernacle can be probably traced back onesto verso restoration intervention. Durante matchocean fact, this alpine species, paio to its excellent technological characteristics, has been widely marketed and often has been found con restored wooden structures durante Sicily .
Chestnut wood was used mediante the back structural elements of the altar due puro its excellent physical and mechanical properties in relation puro the density. Moreover, the chestnut wood has verso natural durability and it exhibits per moderate shrinking [21, 22]. Chestnut wood has been used durante Italy especially for roof beams and also for the outer surface of the doors due to the properties of its heartwood. The chestnut heartwood has verso natural pleasant colour that darkens during time [23, 24].
The walnut wood was found in the winch drum (cylindrical element on which the ropes are wrapped in order preciso raise the statue). The use of this species is related mainly to the low coefficient of shrinkage that ensures dimensional stability during the thermo hygrometric variations .
The different species within the Pinus, Quercus, and Populus genera cannot be distinguished exclusively on the basis of anatomical features [21, 25–27]. Therefore the identification of botanical species was not obtained.
Pine wood has been used for the realization of some plugging elements on the back side of the Machine. These elements probably were movable, but today we are not able to understand their function.
The decoration elements are made of poplar, per wood species widely used mediante Italy for the creation of painted panels and other decorated works of art [21, 28]. Mediante fact, it is characterized by low density, easy seasoning and processing, and colour homogeneity that make it particularly suited sicuro apply the painted layers, mediante spite of this wood could be easily attacked by xylophages.
Microclimatic analysis
The microclimate campaign was carried out during the summer that can be considered the most critical period for the artefact. Moreover, sopra August the Machine is moved on the occasion of religious celebrations and many people crowd the church influencing the microclimate.
It must be stressed that the monitoring campaign was short but, we think, significant and useful for the purpose of this work that is the overall study of a peculiar and interesting artefact with the hope that it could be restored and conserved durante the most appropriate way.