Moreover, several wood defects like knots and ring shake were identified

Mediante fact, summer sultriness is particularly high during August per South Italy

As referred per the preparazione 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 puro the manufacturing process, esatto the Altar Machine usage, and esatto the microclimate durante 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 per great importance mediante the technological and historical artistic study of per wooden artefact due esatto possible implications relating onesto the conservation. Sopra 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 in relation preciso the technological characteristics of the altar elements. The results are summarized con 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 con the tabernacle can be probably traced back preciso per restoration intervention. Mediante fact, this alpine species, paio sicuro its excellent technological characteristics, has been widely marketed and often has been found per restored wooden structures mediante Sicily .

Chestnut wood was used in the back structural elements of the altar coppia esatto its excellent physical and mechanical properties per relation esatto the density. Moreover, the chestnut wood has verso natural durability and it exhibits a moderate shrinking [21, 22]. Chestnut wood has been used mediante Italy especially for roof beams and also for the outer surface of the doors paio esatto the properties of its heartwood. The chestnut heartwood has a natural pleasant colour that darkens during time [23, 24].

The walnut wood was found durante the winch drum (cylindrical element on which the ropes are wrapped per order onesto raise the statue). The use of this species is related mainly sicuro 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 sicuro understand their loveaholics function.

The decoration elements are made of poplar, a wood species widely used in Italy for the creation of painted panels and other 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 onesto 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, con 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 in the most appropriate way.