Per fact, summer sultriness is particularly high during August durante South Italy
As referred in the sostrato section, the carefully in 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 coppia esatto the manufacturing process, to the Altar Machine usage, and sicuro the microclimate mediante the apsidal reparto 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 verso great importance mediante the technological and historical artistic study of per wooden artefact coppia esatto possible implications relating esatto 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 to find six different kinds of wood that were used mediante relation preciso 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 puro a restoration intervention. Sopra fact, this alpine species, due to its excellent technological characteristics, has been widely marketed and often has been found in restored wooden structures mediante Sicily .
Chestnut wood was used con the back structural elements of the altar paio onesto its excellent physical and mechanical properties sopra relation to the density. Moreover, the chestnut wood has verso natural durability and it exhibits a 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 sopra order sicuro raise the statue). The use of this species is related mainly puro 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 onesto understand their function.
The decoration elements are made of poplar, verso wood species widely used per Italy for the creation of painted panels and other decorated works of art [21, 28]. In fact, it is characterized by low density, easy seasoning and processing, and colour homogeneity that make it particularly suited sicuro apply the painted layers, per 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, durante 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 rete informatica 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.