Mediante fact, summer sultriness is particularly high during August durante South Italy
As referred mediante the retroterra section, the carefully per 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 esatto the manufacturing process, esatto the Altar Machine usage, and esatto the microclimate in the apsidal sezione 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 sopra the technological and historical artistic study of per wooden artefact due puro possible implications relating preciso the conservation. Mediante 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 preciso find six different kinds of wood that were used sopra relation preciso the technological characteristics of the altar elements. The results are summarized con Table 3.
The wood bronymate 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 durante the tabernacle can be probably traced back to a restoration intervention. Per fact, this alpine species, paio onesto its excellent technological characteristics, has been widely marketed and often has been found sopra restored wooden structures sopra Sicily .
Chestnut wood was used durante the back structural elements of the altar paio esatto its excellent physical and mechanical properties in relation preciso the density. Moreover, the chestnut wood has per natural durability and it exhibits verso moderate shrinking [21, 22]. Chestnut wood has been used sopra Italy especially for roof beams and also for the outer surface of the doors due puro the properties of its heartwood. The chestnut heartwood has per natural pleasant colour that darkens during time [23, 24].
The walnut wood was found per the winch drum (cylindrical element on which the ropes are wrapped mediante order puro 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, a wood species widely used per Italy for the creation of painted panels and other decorated works of art [21, 28]. Durante fact, it is characterized by low density, easy seasoning and processing, and colour homogeneity that make it particularly suited onesto apply the painted layers, per spite of this wood could be easily attacked by xylophages.
The microclimate campaign was carried out during the summer that can be considered the most critical period for the artefact. Moreover, in 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 sistema that is the overall study of verso peculiar and interesting artefact with the hope that it could be restored and conserved in the most appropriate way.