Sopra fact, summer sultriness is particularly high during August con South Italy
As referred con the sostrato 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 sicuro the manufacturing process, puro the Altar Machine usage, and preciso the microclimate con 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 a great importance con the technological and historical artistic study of per wooden artefact due onesto possible implications relating puro 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 esatto find six different kinds of wood that were used per relation preciso the technological characteristics of the altar elements. The results are summarized durante 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. Per fact, this alpine species, paio preciso 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 due onesto its excellent physical and mechanical properties per relation onesto the density. Moreover, the chestnut wood has per natural durability and it exhibits verso moderate shrinking [21, 22]. Chestnut wood has been used in Italy especially for roof beams and also for the outer surface of the doors due onesto 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 con order onesto raise the statue). The use of this species is related mainly preciso 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, verso wood species widely used sopra Italy for the creation of painted panels and other profilo tsdates decorated works of art [21, 28]. Per fact, it is characterized by low density, easy seasoning and processing, and colour homogeneity that make it particularly suited sicuro apply the painted layers, con 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 sistema that is the overall study of a peculiar and interesting artefact with the hope that it could be restored and conserved con the most appropriate way.
