The wooden foundations of Ponte di Rialto (Rialto Bridge), the oldest and most famous of the four... more The wooden foundations of Ponte di Rialto (Rialto Bridge), the oldest and most famous of the four bridges spanning the Grand Canal in Venice, Italy, were analysed in order to determine the tree species used to construct the foundation, to examine the timber's present-day physical and mechanical properties and to identify construction periods. The material recovered during geotechnical surveys underwent micro-morphological, physical, chemical and mechanical analyses. The radiocarbon method was used for dating purposes. The footings of the bridge's foundations, mostly consisting of alder wood, were shown to be in good overall condition generally. A comparison of normal and polarised light images of wooden cross-sections showed abundant crystalline cellulose within the cell walls, indicating that the state of conservation of the waterlogged samples is very close to that of sound alder wood. Only one alder sample showed signs of severe bacterial attack, mostly concentrated in the fibre cell walls. Radiocarbon dating identified two distinct construction periods. One sample dates to 1570 AD ± 85, whilst another dates to the year 960 AD ± 59. The later dating corresponds to the construction of the stone bridge that still exists today. The earlier period, around the year 1000, likely refers to the foundations of the first bridge, built after several pontoon bridges, and corresponding to the initial Ponte della Moneta.
The present paper deals with wood from Venice historic centre foundation elements. Samples were t... more The present paper deals with wood from Venice historic centre foundation elements. Samples were taken from both piles and planking (horizontal elements positioned above the pile heads), in 5 out of 6 districts of Venice. Considering the watery milieu, the diagnostic methodology for waterlogged archaeological wood was adopted, performing anatomical, chemical and physical characterisations. Our results show that the wood used for Venetian foundation elements belong to a small group of 5–6 species (alder, larch, oak, pine, elm and spruce, although the latter was probably of more recent introduction). Most of the analysed samples evidenced decay, which in some cases was high (residual basic densities of only 32%, and values of the ratio holocellulose to lignin as low as 0.3). It was evidenced how the state of preservation of wood was related to several factors, including: thickness of the element, depth of burial, horizontal/vertical position, and wood species. It was also shown how ash content does not reflect the state of preservation of waterlogged material, as it is sometimes reported in the literature. The diffuse decay was apparently not related to the general stability of the buildings under study.
The grading of the anatomical preservation of cells inside waterlogged archaeological wood can be... more The grading of the anatomical preservation of cells inside waterlogged archaeological wood can be obtained by linking qualitative information obtained by microscopes with quantitative results inferred from physical characterisation. This study shows an approach to grading based on the microscopic analyses of 81 cores coming from poles of the pile-dwelling of Fiavè (IVeII millennia B.C.). Observations and physical analyses were undertaken on three different sectors of each core, taking into account their different state of preservation. In total 239 samples were analysed. The analyses identified 38 cores of larch (Larix decidua Mill.), 24 of spruce (Picea abies Karst.) and 19 of silver fir (Abies alba Mill.). Based on the morphology of decay, clear signs of biological attacks were identified: soft rot cavities, pointed ended, moving along the micro-fibrillar orientation of the cell wall, and " V "-shaped notches of eroded cell wall beyond the granular aspect in cross sections of heavily degraded cells. Results of classification (5 classes) according to micromorphological observations were compared to MWC values, for validation. This way we could verify an increase of average MWC with increasing micromorphological decay class, thus proving the reliability of the grading process. However, the micromorphological grading appeared more informative about the first stages of the attack.
This paper deals with the description of the analysis performed to characterize the state of pres... more This paper deals with the description of the analysis performed to characterize the state of preservation of the wooden artefacts recently discovered at the site of Herculaneum, Italy. During 2009, several wooden artefacts were brought to light during maintenance work at Herculaneum. They were attributed to both the roofing elements and the ceiling of the House of the Relief of Telephus. The roof was found mainly disassembled; nevertheless, it was an extraordinary archaeological find, because it represents a unique vestige of a Roman roof and, moreover, the aspect of both the structural and the decorative panels, where portions of the original polychrome decoration and traces of gilding were still preserved, appeared almost intact. Within the framework of the Herculaneum Conservation Project, a diagnostic study was undertaken to characterize the state of preservation of the wood constituting the roof, and also including the decorated panels of the ceiling, in order to determine a consolidation process able to structurally support the decayed wood without damaging the residual poly-chrome decoration. The results of the micromorphological, chemical and physical characterization of the wood, as a combined diagnostic process, are reported. A first proposal of a possible consolidation methodology based on the analytical results is also suggested.
In Italy there is a standardisation working group on the problematic of wood in Cultural Heritage... more In Italy there is a standardisation working group on the problematic of wood in Cultural Heritage. This group, which is named GL20 “Cultural Heritage wooden artefacts”, is producing technical standards devoted to aspects which are every day present in professional work carried out by architects, engineers, wood technologists, archaeologists, art-historians…. In this poster the UNI standard 11141 which deals about ”guidelines for dendrochronolocail dating of wood in Cultural Heritage” is presented.
This paper describes the study of a 31-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco... more This paper describes the study of a 31-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand located in Southern Italy, which was thinned 19 years after planting. The aim of the study is to evaluate the influence of three thinning treatments (unthinned, selective, and geometrical) performed twelve years later on wood density (WD), moisture content, shrinkage, ring width (RW), latewood proportion (LW%), modulus of elasticity, compression (CS), and bending strength (BS). The WD was higher in the unthinned stand. LW% and BS were lowest in the selective thinning and in the geometrical thinning, respectively. No significant differences were found in other variables. In addition, the thinning processes mostly affected the medium tree class more than the dominant and suppressed ones. Regression analysis established a correlation between mechanical characteristics and WD, RW and LW%. Mechanical strength is strongly correlated with WD than other variables. The stepwise model showed that WD and RW are most closely related to the behavior of CS, whereas only WD explained variation in BS. Stand density reduction may improve the development of stands without greatly affecting wood quality.
A multi-technique approach was employed to study a decorated Egyptian wooden sarcophagus (XXV–XXV... more A multi-technique approach was employed to study a decorated Egyptian wooden sarcophagus (XXV–XXVI dynasty, Third Intermediate Period), belonging to the Museo del Vicino Oriente of the Sapienza University of Rome. Portable non-invasive unilateral NMR was applied to evaluate the conservation state of the sarcophagus. Moreover, using unilateral NMR, a non-invasive analytical protocol was established to detect the presence of organic substances on the surface and/or embedded in the wooden matrix. This protocol allowed for an educated sampling campaign aimed at further investigating the state of degradation of the wood and the presence of organic substances by 13C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. The composition of the painted layer was analysed by optical microscopy (OM), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS), Raman and surface enhanced (resonance) Raman spectroscopy (SERS/SERRS), infrared and GC–MS techniques, evidencing original components such as clay minerals, Egyptian green, indigo, natural gums, and also highlighting restoration pigments and alteration compounds. The identification of the wood, of great value for the reconstruction of the history of the artwork, was achieved by means of optical microscopy.
Forty years ago in a xxth-century church in Torino, a small fire partially burned some of the dec... more Forty years ago in a xxth-century church in Torino, a small fire partially burned some of the decorative external boards of the sound-box of the organ. The focus of this present work was to find a treatment able to consolidate partially burnt wood in dry conditions, in which the external charred layer would be lost if not well preserved because of its incoherence. The product had to be applied onsite on an architectural structure intended to be reused again (and not simply exhibited). This circumstance is rarely encountered in the conservation of wooden Cultural Heritage. The efficacy of treatments was evaluated on the basis of a suitable and original experimental methodology, which took into account both the immediate and long-term behaviour of the various tested products. Although the opportunity to carry out this work came from a real case, both the selected product and the set up evaluation methodology have a general validity and they can be effectively used in other similar situations in which a slight antipowdering effect is required for treatment.
L’utilizzo in campo artistico del legno è vasto, sebbene le opere lignee spesso siano state consi... more L’utilizzo in campo artistico del legno è vasto, sebbene le opere lignee spesso siano state considerate semplici lavori artigianali. Comunemente si ritiene che il diffuso impiego derivi al legno dalla sua larga disponibilità, dalla facile lavorabilità e da una leggerezza evidente, se comparata con quella di altri materiali usati in campo artistico, e sorprendente, in rapporto alle elevate prestazioni meccaniche tipiche di questo materiale. Esistono altri materiali compositi largamente disponibili, facilmente lavorabili e leggeri. Nella statuaria abbiamo numerosi esempi di opere polimateriche leggere, plasmate e finite con estrema cura, realizzate con materiali di facile disponibilità come la terracotta, o addirittura di scarto, come la cartapesta. Si tratta di materiali per i quali esistono non rari esempi di utilizzo, ma che non hanno avuto la stessa fortuna del legno. Evidentemente c’è qualcosa di più: non sono sufficienti a giustificare un così ampio utilizzo del legno le tre rag...
The wooden foundations of Ponte di Rialto (Rialto Bridge), the oldest and most famous of the four... more The wooden foundations of Ponte di Rialto (Rialto Bridge), the oldest and most famous of the four bridges spanning the Grand Canal in Venice, Italy, were analysed in order to determine the tree species used to construct the foundation, to examine the timber's present-day physical and mechanical properties and to identify construction periods. The material recovered during geotechnical surveys underwent micro-morphological, physical, chemical and mechanical analyses. The radiocarbon method was used for dating purposes. The footings of the bridge's foundations, mostly consisting of alder wood, were shown to be in good overall condition generally. A comparison of normal and polarised light images of wooden cross-sections showed abundant crystalline cellulose within the cell walls, indicating that the state of conservation of the waterlogged samples is very close to that of sound alder wood. Only one alder sample showed signs of severe bacterial attack, mostly concentrated in the fibre cell walls. Radiocarbon dating identified two distinct construction periods. One sample dates to 1570 AD ± 85, whilst another dates to the year 960 AD ± 59. The later dating corresponds to the construction of the stone bridge that still exists today. The earlier period, around the year 1000, likely refers to the foundations of the first bridge, built after several pontoon bridges, and corresponding to the initial Ponte della Moneta.
The present paper deals with wood from Venice historic centre foundation elements. Samples were t... more The present paper deals with wood from Venice historic centre foundation elements. Samples were taken from both piles and planking (horizontal elements positioned above the pile heads), in 5 out of 6 districts of Venice. Considering the watery milieu, the diagnostic methodology for waterlogged archaeological wood was adopted, performing anatomical, chemical and physical characterisations. Our results show that the wood used for Venetian foundation elements belong to a small group of 5–6 species (alder, larch, oak, pine, elm and spruce, although the latter was probably of more recent introduction). Most of the analysed samples evidenced decay, which in some cases was high (residual basic densities of only 32%, and values of the ratio holocellulose to lignin as low as 0.3). It was evidenced how the state of preservation of wood was related to several factors, including: thickness of the element, depth of burial, horizontal/vertical position, and wood species. It was also shown how ash content does not reflect the state of preservation of waterlogged material, as it is sometimes reported in the literature. The diffuse decay was apparently not related to the general stability of the buildings under study.
The grading of the anatomical preservation of cells inside waterlogged archaeological wood can be... more The grading of the anatomical preservation of cells inside waterlogged archaeological wood can be obtained by linking qualitative information obtained by microscopes with quantitative results inferred from physical characterisation. This study shows an approach to grading based on the microscopic analyses of 81 cores coming from poles of the pile-dwelling of Fiavè (IVeII millennia B.C.). Observations and physical analyses were undertaken on three different sectors of each core, taking into account their different state of preservation. In total 239 samples were analysed. The analyses identified 38 cores of larch (Larix decidua Mill.), 24 of spruce (Picea abies Karst.) and 19 of silver fir (Abies alba Mill.). Based on the morphology of decay, clear signs of biological attacks were identified: soft rot cavities, pointed ended, moving along the micro-fibrillar orientation of the cell wall, and " V "-shaped notches of eroded cell wall beyond the granular aspect in cross sections of heavily degraded cells. Results of classification (5 classes) according to micromorphological observations were compared to MWC values, for validation. This way we could verify an increase of average MWC with increasing micromorphological decay class, thus proving the reliability of the grading process. However, the micromorphological grading appeared more informative about the first stages of the attack.
This paper deals with the description of the analysis performed to characterize the state of pres... more This paper deals with the description of the analysis performed to characterize the state of preservation of the wooden artefacts recently discovered at the site of Herculaneum, Italy. During 2009, several wooden artefacts were brought to light during maintenance work at Herculaneum. They were attributed to both the roofing elements and the ceiling of the House of the Relief of Telephus. The roof was found mainly disassembled; nevertheless, it was an extraordinary archaeological find, because it represents a unique vestige of a Roman roof and, moreover, the aspect of both the structural and the decorative panels, where portions of the original polychrome decoration and traces of gilding were still preserved, appeared almost intact. Within the framework of the Herculaneum Conservation Project, a diagnostic study was undertaken to characterize the state of preservation of the wood constituting the roof, and also including the decorated panels of the ceiling, in order to determine a consolidation process able to structurally support the decayed wood without damaging the residual poly-chrome decoration. The results of the micromorphological, chemical and physical characterization of the wood, as a combined diagnostic process, are reported. A first proposal of a possible consolidation methodology based on the analytical results is also suggested.
In Italy there is a standardisation working group on the problematic of wood in Cultural Heritage... more In Italy there is a standardisation working group on the problematic of wood in Cultural Heritage. This group, which is named GL20 “Cultural Heritage wooden artefacts”, is producing technical standards devoted to aspects which are every day present in professional work carried out by architects, engineers, wood technologists, archaeologists, art-historians…. In this poster the UNI standard 11141 which deals about ”guidelines for dendrochronolocail dating of wood in Cultural Heritage” is presented.
This paper describes the study of a 31-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco... more This paper describes the study of a 31-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand located in Southern Italy, which was thinned 19 years after planting. The aim of the study is to evaluate the influence of three thinning treatments (unthinned, selective, and geometrical) performed twelve years later on wood density (WD), moisture content, shrinkage, ring width (RW), latewood proportion (LW%), modulus of elasticity, compression (CS), and bending strength (BS). The WD was higher in the unthinned stand. LW% and BS were lowest in the selective thinning and in the geometrical thinning, respectively. No significant differences were found in other variables. In addition, the thinning processes mostly affected the medium tree class more than the dominant and suppressed ones. Regression analysis established a correlation between mechanical characteristics and WD, RW and LW%. Mechanical strength is strongly correlated with WD than other variables. The stepwise model showed that WD and RW are most closely related to the behavior of CS, whereas only WD explained variation in BS. Stand density reduction may improve the development of stands without greatly affecting wood quality.
A multi-technique approach was employed to study a decorated Egyptian wooden sarcophagus (XXV–XXV... more A multi-technique approach was employed to study a decorated Egyptian wooden sarcophagus (XXV–XXVI dynasty, Third Intermediate Period), belonging to the Museo del Vicino Oriente of the Sapienza University of Rome. Portable non-invasive unilateral NMR was applied to evaluate the conservation state of the sarcophagus. Moreover, using unilateral NMR, a non-invasive analytical protocol was established to detect the presence of organic substances on the surface and/or embedded in the wooden matrix. This protocol allowed for an educated sampling campaign aimed at further investigating the state of degradation of the wood and the presence of organic substances by 13C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. The composition of the painted layer was analysed by optical microscopy (OM), scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS), Raman and surface enhanced (resonance) Raman spectroscopy (SERS/SERRS), infrared and GC–MS techniques, evidencing original components such as clay minerals, Egyptian green, indigo, natural gums, and also highlighting restoration pigments and alteration compounds. The identification of the wood, of great value for the reconstruction of the history of the artwork, was achieved by means of optical microscopy.
Forty years ago in a xxth-century church in Torino, a small fire partially burned some of the dec... more Forty years ago in a xxth-century church in Torino, a small fire partially burned some of the decorative external boards of the sound-box of the organ. The focus of this present work was to find a treatment able to consolidate partially burnt wood in dry conditions, in which the external charred layer would be lost if not well preserved because of its incoherence. The product had to be applied onsite on an architectural structure intended to be reused again (and not simply exhibited). This circumstance is rarely encountered in the conservation of wooden Cultural Heritage. The efficacy of treatments was evaluated on the basis of a suitable and original experimental methodology, which took into account both the immediate and long-term behaviour of the various tested products. Although the opportunity to carry out this work came from a real case, both the selected product and the set up evaluation methodology have a general validity and they can be effectively used in other similar situations in which a slight antipowdering effect is required for treatment.
L’utilizzo in campo artistico del legno è vasto, sebbene le opere lignee spesso siano state consi... more L’utilizzo in campo artistico del legno è vasto, sebbene le opere lignee spesso siano state considerate semplici lavori artigianali. Comunemente si ritiene che il diffuso impiego derivi al legno dalla sua larga disponibilità, dalla facile lavorabilità e da una leggerezza evidente, se comparata con quella di altri materiali usati in campo artistico, e sorprendente, in rapporto alle elevate prestazioni meccaniche tipiche di questo materiale. Esistono altri materiali compositi largamente disponibili, facilmente lavorabili e leggeri. Nella statuaria abbiamo numerosi esempi di opere polimateriche leggere, plasmate e finite con estrema cura, realizzate con materiali di facile disponibilità come la terracotta, o addirittura di scarto, come la cartapesta. Si tratta di materiali per i quali esistono non rari esempi di utilizzo, ma che non hanno avuto la stessa fortuna del legno. Evidentemente c’è qualcosa di più: non sono sufficienti a giustificare un così ampio utilizzo del legno le tre rag...
This paper deals with the scientific identification of species utilised for the
production of woo... more This paper deals with the scientific identification of species utilised for the production of wooden sculptures in the exhibition, Il Teatro del Sacro (Asti, 2009), of statues dating back to 17th and 18th centuries. All the statues came from the diocese of Asti (Northwest Italy). Problems in the sample drawing are analysed, together with the results, described by period and author, on the basis of the identified species. Almost all the statues were made of poplar or willow wood, except two, made of walnut wood. The paper describes also the principal technological characteristics of the identified woods, considering specifically their utilisation for carving works.
Le bois est la matière qui se trouve sous
l’écorce de la tige, “une substance dure, compacte,
sol... more Le bois est la matière qui se trouve sous l’écorce de la tige, “une substance dure, compacte, solide, qui constitue la racine, la tige et les branches des arbres et arbrisseaux” (dictionnaire Littré). Cette définition nous indique que le bois est une matière première produite à partir de plantes ligneuses, mais elle ne nous dit rien de sa constitution et de son rapport à l’homme. En effet, pour la plupart des gens, le bois est un objet du quotidien, tels la chaise en hêtre, la poutre en chêne, la table en merisier, la rambarde en iroko, la guitare en épicéa et en érable sycomore ondé, la latte en châtaignier, le pont de voilier en teck, la sculpture en tilleul, la cagette en peuplier, le bardage en douglas, le lambris en pin maritime, la bibliothèque en padouk, la bûche en charme, le coffret en cyprès, l’armoire en noyer, la commode en acajou, le manche d’outil en frêne, la moulure en pin sylvestre, l’établi en bossé, le piquet de la vigne en robinier, le parquet en wengé, l’arc en if, l’escalier en sipo, la frisette en platane, le pilier en cocotier, le bardeau en mélèze, le moyeu de roue en orme…
L’utilizzo in campo artistico del legno è vasto,
sebbene le opere lignee spesso siano state consi... more L’utilizzo in campo artistico del legno è vasto, sebbene le opere lignee spesso siano state considerate semplici lavori artigianali. Comunemente si ritiene che il diffuso impiego derivi al legno dalla sua larga disponibilità, dalla facile lavorabilità e da una leggerezza evidente, se comparata con quella di altri materiali usati in campo artistico, e sorprendente, in rapporto alle elevate prestazioni meccaniche tipiche di questo materiale. Esistono altri materiali compositi largamente disponibili, facilmente lavorabili e leggeri. Nella statuaria abbiamo numerosi esempi di opere polimateriche leggere, plasmate e finite con estrema cura, realizzate con materiali di facile disponibilità come la terracotta, o addirittura di scarto, come la cartapesta. Si tratta di materiali per i quali esistono non rari esempi di utilizzo, ma che non hanno avuto la stessa fortuna del legno. Evidentemente c’è qualcosa di più: non sono sufficienti a giustificare un così ampio utilizzo del legno le tre ragioni indicate inizialmente1. Lo scopo di questo contributo è evidenziare gli apporti informativi che le identificazioni delle specie legnose possono fornire all’interno dello studio storico-artistico e del restauro dei manufatti lignei.
The sanctuary of San Michele Arcangelo dates back to 493 AD and is listed in the UNESCO World Her... more The sanctuary of San Michele Arcangelo dates back to 493 AD and is listed in the UNESCO World Heritage. The door of the sanctuary is considered a "perpetual holy door". It is made of bronze panels covering a wooden structure, which was investigated in order to identify the tree species and the dating. The wooden structure is made mainly by oak with few elements of larch. The oak has been dated through radiocarbon analysis to the year 1385 AD ± 65, while the larch was dated through dendrochronology to the year 1689. None of the wooden elements corresponds to the original structure, but they are the result of different restoration works. The oldest intervention, dated around 1400 AD, is not mentioned in any documentation or source, while the recentest one, towards the half of 1700, is probably the consequence of the fire that damaged the door in that time.
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Papers by Nicola Macchioni
production of wooden sculptures in the exhibition, Il Teatro del Sacro (Asti, 2009), of statues dating back to 17th and 18th centuries. All the statues came from the diocese of Asti (Northwest Italy). Problems in the sample drawing are analysed, together with the results, described by period and author, on the basis of the identified species. Almost all the statues were made of poplar or willow wood, except two, made of walnut wood. The paper describes also the principal technological characteristics of the identified woods, considering specifically their utilisation for carving works.
l’écorce de la tige, “une substance dure, compacte,
solide, qui constitue la racine, la tige et
les branches des arbres et arbrisseaux” (dictionnaire
Littré).
Cette définition nous indique que le bois
est une matière première produite à partir
de plantes ligneuses, mais elle ne nous dit
rien de sa constitution et de son rapport à
l’homme. En effet, pour la plupart des gens, le
bois est un objet du quotidien, tels la chaise
en hêtre, la poutre en chêne, la table en merisier,
la rambarde en iroko, la guitare en épicéa
et en érable sycomore ondé, la latte en châtaignier,
le pont de voilier en teck, la sculpture
en tilleul, la cagette en peuplier, le bardage
en douglas, le lambris en pin maritime, la bibliothèque
en padouk, la bûche en charme, le
coffret en cyprès, l’armoire en noyer, la commode
en acajou, le manche d’outil en frêne, la
moulure en pin sylvestre, l’établi en bossé, le
piquet de la vigne en robinier, le parquet en
wengé, l’arc en if, l’escalier en sipo, la frisette
en platane, le pilier en cocotier, le bardeau en
mélèze, le moyeu de roue en orme…
sebbene le opere lignee spesso siano state considerate
semplici lavori artigianali. Comunemente si ritiene
che il diffuso impiego derivi al legno dalla sua
larga disponibilità, dalla facile lavorabilità e da una
leggerezza evidente, se comparata con quella di altri
materiali usati in campo artistico, e sorprendente,
in rapporto alle elevate prestazioni meccaniche
tipiche di questo materiale. Esistono altri materiali
compositi largamente disponibili, facilmente lavorabili
e leggeri. Nella statuaria abbiamo numerosi
esempi di opere polimateriche leggere, plasmate e
finite con estrema cura, realizzate con materiali di
facile disponibilità come la terracotta, o addirittura
di scarto, come la cartapesta. Si tratta di materiali
per i quali esistono non rari esempi di utilizzo, ma
che non hanno avuto la stessa fortuna del legno.
Evidentemente c’è qualcosa di più: non sono sufficienti
a giustificare un così ampio utilizzo del legno
le tre ragioni indicate inizialmente1. Lo scopo
di questo contributo è evidenziare gli apporti informativi
che le identificazioni delle specie legnose
possono fornire all’interno dello studio storico-artistico
e del restauro dei manufatti lignei.