Alexa Dufraisse | Centre National de la Recherche Scientifique / French National Centre for Scientific Research (original) (raw)
Books by Alexa Dufraisse
Papers by Alexa Dufraisse
Frontiers in Ecology and Evolution, 2022
In many societies, livelihood strategies are based on a combination of economic strategies, inclu... more In many societies, livelihood strategies are based on a combination of economic strategies, including natural resources such as trees for wood, leaves, and fruits. Archeological wood charcoals are residues of human activity related to fire. They provide evidence of fuelwood and, in some contexts, timber, handcraft activities, and fruit production. They represent a detailed record of the way ancient woodlands were exploited. However, charcoal analyses are often confined to the study of taxa and their relative frequency, and socio-economic interpretations are thus limited. In the last two decades, dendro-anthracological studies have been developed. Tree-ring widths, radius of curvature, and carbon isotope contents are increasingly used as indicators of wood gathering practices, woodland management and climate. Nevertheless, in the absence of standards, measurement procedures and data processing are very diverse. The challenge for archeological charcoal analyses is thus to improve anal...
Bulletin de la Société préhistorique de France, 2018
Cette comparaison des résultats palynologiques (73 spectres) et anthracologiques (9 sites, 305 pr... more Cette comparaison des résultats palynologiques (73 spectres) et anthracologiques (9 sites, 305 prélèvements) a pour but d'appréhender l'environnement dans lequel les sites sont implantés et la dynamique de la végétation au cours du Néolithique dans le sud du bassin de l'Escaut. Les premiers groupes néolithiques sont arrivés dans un milieu où prédominent le tilleul, le noisetier et le chêne. Dans les assemblages anthracologiques du Rubané (5 200-5 000 BC), la domination du noisetier pourrait être liée à un retard dans la reconquête de la chênaie aux sources de la Dendre, mais aussi à des pratiques humaines mésolithiques antérieures. Le tilleul est sous-représenté dans les ressources en bois de feu par rapport à sa disponibilité près des sites néolithiques. Durant la seconde moitié de l'Atlantique, l'environnement ligneux évolue peu, sauf l'aulnaie qui se développe en fond de vallée. Les communautés du groupe de Spiere (4 200-3 800 BC) ont parcouru des milieux diversifiés pour la collecte du combustible. Le chêne est généralement largement dominant posant la question de sa surreprésentation en anthracologie au détriment du tilleul et du noisetier encore bien visibles en palynologie. La ripisylve est bien enregistrée par l'anthracologie, à différent stade de son développement. L'aulnaie mature n'est visible que sur les sites à enceinte et la collecte des lisières à Maloideae sont particulièrement marquées à cette période. Au Subboréal, on assiste à une augmentation de l'humidité atmosphérique avec l'arrivée du hêtre (en palynologie) et de l'if (en anthracologie). Les groupes du Deûle-Escaut (2 900-2 200 BC) ont collecté leur combustible au sein de la chênaie-frênaie et, selon les sites, les lisières sur sols sec (sites d'habitat) ou l'aulnaie mature (sites à enceinte). L'importance de la ripisylve et du frêne peut être corrélée à la localisation des sites en bordure de berge, mais peut-être aussi, par les modalités d'aménagement de ces zones humides. En plus de l'if, l'érable est également caractéristique de la période.
ABSTRACT The charcoal analyses realised on approximately ten Neolithic wetland sites of the Circu... more ABSTRACT The charcoal analyses realised on approximately ten Neolithic wetland sites of the Circum Alpine Region have allowed us to go beyond the classical interpretation of the charcoal diagrams. In order to extend the range of hypotheses for the interpretation of these diagrams, we tested an ethno-archaeological approach, which is a first in terms of anthracological fieldwork. A first investigation in the Yeleme Valley (New-Guinea) in 2005 indicated that this method is a valuable tool to study the different ways of visualising the territory and the forest, and how they are translated in the charcoal assemblages; particularly so for prehistoric periods when the conception and the organisation patterns of the territory were most likely very different from our own. This approach therefore provides us with a novel way of reflecting, which must be integrated into the charcoal diagram interpretation, and thus propose new working hypothesis to be tested on the past.
Quaternary International, 2021
We present and model new radiocarbon data for the Neolithic marshes of Marais de Saint-Gond Marne... more We present and model new radiocarbon data for the Neolithic marshes of Marais de Saint-Gond Marne in France. We then provide the first radiocarbon-based synthesis of human activity in this region. The earliest flint mine pits dug in France were dated to between 7518 and 7356 cal BC (95% probability) in the Mesolithic period. A Neolithic sequence of activity has been reconstructed in detail for the mine and hypogeums in the Vert-la-Gravelle “La Crayere” site. Using summed probability distribution frequencies with new radiocarbon results from flint mines, hypogeum-burials and settlements, we show the peak of regional population is consistent with the advent of the hypogeum construction during the Neolithique recent/Neolithique final between 3650 and 2900 cal BC (95% probability).
Quaternary International, 2020
Quaternary International, 2020
Journal of Archaeological Science: Reports, 2020
Les Nouvelles de l'archéologie, 2018
La foret des hommes La foret tient un role essentiel dans la regulation du climat et sa place dan... more La foret des hommes La foret tient un role essentiel dans la regulation du climat et sa place dans le cycle du carbone est determinante. Refuge de biodiversite menace par les activites humaines, la foret est aussi un lieu de vie de nombreuses communautes. Elle est pourvoyeuse de ressources essentielles (fruits, bois, plantes medicinales, gibier), les hommes y ont installe champs, troupeaux et villages. Les societes ont transforme la foret sauvage en une foret humanisee, utile, domestique : « ...
Quaternary International, 2017
Quaternary International, 2017
Among the main parameters contributing to the characterization of firewood exploitation modes, th... more Among the main parameters contributing to the characterization of firewood exploitation modes, the age of the collected wood is very difficult to assess in anthracology. In this paper, we propose an original way to investigate the age of the exploited wood, the heartwood formation process which takes place in 20–25-year-old deciduous oak trees. The formation of tyloses in earlywood vessels is an important feature of the changeover of sapwood to heartwood. However, tylosis formation also occurs in sapwood. Therefore, the observation of the mere presence of tyloses in vessels, as routinely performed in anthracology, is not sufficient to distinguish sapwood from heartwood. The aim of this study was thus to use the proportion of vessels sealed by tyloses as a discriminating marker between sapwood and heartwood applicable to anthracology in order to characterize firewood exploitation in the past. The trunks and branches of ten deciduous oak trees ranging from 15 to 60 years old were sampled in three French sites. For an application to archaeological charcoal (tyloses are preserved until 800 °C), thresholds of less than 65% for sapwood and up to 85% for heartwood appear to be significant at the population level for deciduous oak (Quercus petraea/robur) in a temperate climate. Besides the indication of the minimal age (ca. 25 years old in the case of deciduous oak), the variability of the proportion of vessels with tyloses in sapwood is explored as a good indicator of the vitality of the wood which opens new prospects for the exploitation of dendro-anthracological parameters, such as the discrimination of branch wood.
Quaternary International, 2017
Quaternary International, 2017
Abstract The Franche-Comte region played an important role in the iron industry since at least th... more Abstract The Franche-Comte region played an important role in the iron industry since at least the Hallstatt Period, but particularly since the industrial revolution (from the end of the 18th century). The presence of thousands of charcoal kilns in the main forest of Besancon (regional capital) is the subject of this study. The aim was to further our understanding of these archaeological objects, and to characterize the impact of charcoal production on the past vegetation. A geophysical survey (magnetic susceptibility) was conducted on two platforms. Charcoal analyses of 11 charcoal kilns and a regressive approach on the current vegetation were undertaken for comparative purposes. The platforms are modern and seem to have been used several times during a short 250-year period. Based on historical sources and compared with forests used for the iron industry, the vegetation of the forest of Chailluz appears to have been harvested for a variety of purposes, notably the iron industry and domestic use. Tree species used to produce charcoal were correlated with the environmental offering and site conditions but charcoal production seemed to open the forest structure. More light demanding taxa and fewer shade-tolerant species than nowadays have been observed.
ABSTRACT Les différents niveaux archéologiques du site du Petit-Chasseur à Sion ont livré un tota... more ABSTRACT Les différents niveaux archéologiques du site du Petit-Chasseur à Sion ont livré un total de 583 charbons de bois répartis entre les niveaux Néolithique moyen I et Néolithique moyen II appartenant à la phase ancienne « Cortaillod type Petit-Chasseur ». Ces charbons sont principalement issus du bois utilisé comme combustible. Une petite part est également attribuée au bois d’architecture. L’analyse anthracologique du site du Petit-Chasseur est la première réalisée en Valais central en Suisse. Pour cette étude, deux axes ont été privilégiés : l’un, plutôt environnemental, propose un essai de restitution de la composition et des transformations des boisements proches du site ; l’autre, plus archéologique, aborde la gestion du bois à l’échelle du village pour la période du Cortaillod type Petit-Chasseur.
Sagvntvm Extra, Jan 12, 2011
This study evaluates the management of different sizes of firewood utilised in the Argaric settle... more This study evaluates the management of different sizes of firewood utilised in the Argaric settlement of Barranco de le Viuda (Lorca, Murcia). A dendrometric analysis was performed to estimate the radius of the curvature of growth rings in charcoal remains identified as Pinus halepensis. An analysis of two archaeological levels and two structures revealed that branches of a small calibre, mostly between two and five cm in diameter, were used. Fragments between five and fourteen cm were less abundant, and pieces larger than fourteen cm in diameter were found in only one of the structures. Treatment of the data by a mathematical model will allow the results to be corrected following certain parameters, such as the shrinkage caused by carbonisation or the error percentage associated with the measurement tool.
Bulletin de la Société préhistorique française, 2009
Frontiers in Ecology and Evolution, 2022
In many societies, livelihood strategies are based on a combination of economic strategies, inclu... more In many societies, livelihood strategies are based on a combination of economic strategies, including natural resources such as trees for wood, leaves, and fruits. Archeological wood charcoals are residues of human activity related to fire. They provide evidence of fuelwood and, in some contexts, timber, handcraft activities, and fruit production. They represent a detailed record of the way ancient woodlands were exploited. However, charcoal analyses are often confined to the study of taxa and their relative frequency, and socio-economic interpretations are thus limited. In the last two decades, dendro-anthracological studies have been developed. Tree-ring widths, radius of curvature, and carbon isotope contents are increasingly used as indicators of wood gathering practices, woodland management and climate. Nevertheless, in the absence of standards, measurement procedures and data processing are very diverse. The challenge for archeological charcoal analyses is thus to improve anal...
Bulletin de la Société préhistorique de France, 2018
Cette comparaison des résultats palynologiques (73 spectres) et anthracologiques (9 sites, 305 pr... more Cette comparaison des résultats palynologiques (73 spectres) et anthracologiques (9 sites, 305 prélèvements) a pour but d'appréhender l'environnement dans lequel les sites sont implantés et la dynamique de la végétation au cours du Néolithique dans le sud du bassin de l'Escaut. Les premiers groupes néolithiques sont arrivés dans un milieu où prédominent le tilleul, le noisetier et le chêne. Dans les assemblages anthracologiques du Rubané (5 200-5 000 BC), la domination du noisetier pourrait être liée à un retard dans la reconquête de la chênaie aux sources de la Dendre, mais aussi à des pratiques humaines mésolithiques antérieures. Le tilleul est sous-représenté dans les ressources en bois de feu par rapport à sa disponibilité près des sites néolithiques. Durant la seconde moitié de l'Atlantique, l'environnement ligneux évolue peu, sauf l'aulnaie qui se développe en fond de vallée. Les communautés du groupe de Spiere (4 200-3 800 BC) ont parcouru des milieux diversifiés pour la collecte du combustible. Le chêne est généralement largement dominant posant la question de sa surreprésentation en anthracologie au détriment du tilleul et du noisetier encore bien visibles en palynologie. La ripisylve est bien enregistrée par l'anthracologie, à différent stade de son développement. L'aulnaie mature n'est visible que sur les sites à enceinte et la collecte des lisières à Maloideae sont particulièrement marquées à cette période. Au Subboréal, on assiste à une augmentation de l'humidité atmosphérique avec l'arrivée du hêtre (en palynologie) et de l'if (en anthracologie). Les groupes du Deûle-Escaut (2 900-2 200 BC) ont collecté leur combustible au sein de la chênaie-frênaie et, selon les sites, les lisières sur sols sec (sites d'habitat) ou l'aulnaie mature (sites à enceinte). L'importance de la ripisylve et du frêne peut être corrélée à la localisation des sites en bordure de berge, mais peut-être aussi, par les modalités d'aménagement de ces zones humides. En plus de l'if, l'érable est également caractéristique de la période.
ABSTRACT The charcoal analyses realised on approximately ten Neolithic wetland sites of the Circu... more ABSTRACT The charcoal analyses realised on approximately ten Neolithic wetland sites of the Circum Alpine Region have allowed us to go beyond the classical interpretation of the charcoal diagrams. In order to extend the range of hypotheses for the interpretation of these diagrams, we tested an ethno-archaeological approach, which is a first in terms of anthracological fieldwork. A first investigation in the Yeleme Valley (New-Guinea) in 2005 indicated that this method is a valuable tool to study the different ways of visualising the territory and the forest, and how they are translated in the charcoal assemblages; particularly so for prehistoric periods when the conception and the organisation patterns of the territory were most likely very different from our own. This approach therefore provides us with a novel way of reflecting, which must be integrated into the charcoal diagram interpretation, and thus propose new working hypothesis to be tested on the past.
Quaternary International, 2021
We present and model new radiocarbon data for the Neolithic marshes of Marais de Saint-Gond Marne... more We present and model new radiocarbon data for the Neolithic marshes of Marais de Saint-Gond Marne in France. We then provide the first radiocarbon-based synthesis of human activity in this region. The earliest flint mine pits dug in France were dated to between 7518 and 7356 cal BC (95% probability) in the Mesolithic period. A Neolithic sequence of activity has been reconstructed in detail for the mine and hypogeums in the Vert-la-Gravelle “La Crayere” site. Using summed probability distribution frequencies with new radiocarbon results from flint mines, hypogeum-burials and settlements, we show the peak of regional population is consistent with the advent of the hypogeum construction during the Neolithique recent/Neolithique final between 3650 and 2900 cal BC (95% probability).
Quaternary International, 2020
Quaternary International, 2020
Journal of Archaeological Science: Reports, 2020
Les Nouvelles de l'archéologie, 2018
La foret des hommes La foret tient un role essentiel dans la regulation du climat et sa place dan... more La foret des hommes La foret tient un role essentiel dans la regulation du climat et sa place dans le cycle du carbone est determinante. Refuge de biodiversite menace par les activites humaines, la foret est aussi un lieu de vie de nombreuses communautes. Elle est pourvoyeuse de ressources essentielles (fruits, bois, plantes medicinales, gibier), les hommes y ont installe champs, troupeaux et villages. Les societes ont transforme la foret sauvage en une foret humanisee, utile, domestique : « ...
Quaternary International, 2017
Quaternary International, 2017
Among the main parameters contributing to the characterization of firewood exploitation modes, th... more Among the main parameters contributing to the characterization of firewood exploitation modes, the age of the collected wood is very difficult to assess in anthracology. In this paper, we propose an original way to investigate the age of the exploited wood, the heartwood formation process which takes place in 20–25-year-old deciduous oak trees. The formation of tyloses in earlywood vessels is an important feature of the changeover of sapwood to heartwood. However, tylosis formation also occurs in sapwood. Therefore, the observation of the mere presence of tyloses in vessels, as routinely performed in anthracology, is not sufficient to distinguish sapwood from heartwood. The aim of this study was thus to use the proportion of vessels sealed by tyloses as a discriminating marker between sapwood and heartwood applicable to anthracology in order to characterize firewood exploitation in the past. The trunks and branches of ten deciduous oak trees ranging from 15 to 60 years old were sampled in three French sites. For an application to archaeological charcoal (tyloses are preserved until 800 °C), thresholds of less than 65% for sapwood and up to 85% for heartwood appear to be significant at the population level for deciduous oak (Quercus petraea/robur) in a temperate climate. Besides the indication of the minimal age (ca. 25 years old in the case of deciduous oak), the variability of the proportion of vessels with tyloses in sapwood is explored as a good indicator of the vitality of the wood which opens new prospects for the exploitation of dendro-anthracological parameters, such as the discrimination of branch wood.
Quaternary International, 2017
Quaternary International, 2017
Abstract The Franche-Comte region played an important role in the iron industry since at least th... more Abstract The Franche-Comte region played an important role in the iron industry since at least the Hallstatt Period, but particularly since the industrial revolution (from the end of the 18th century). The presence of thousands of charcoal kilns in the main forest of Besancon (regional capital) is the subject of this study. The aim was to further our understanding of these archaeological objects, and to characterize the impact of charcoal production on the past vegetation. A geophysical survey (magnetic susceptibility) was conducted on two platforms. Charcoal analyses of 11 charcoal kilns and a regressive approach on the current vegetation were undertaken for comparative purposes. The platforms are modern and seem to have been used several times during a short 250-year period. Based on historical sources and compared with forests used for the iron industry, the vegetation of the forest of Chailluz appears to have been harvested for a variety of purposes, notably the iron industry and domestic use. Tree species used to produce charcoal were correlated with the environmental offering and site conditions but charcoal production seemed to open the forest structure. More light demanding taxa and fewer shade-tolerant species than nowadays have been observed.
ABSTRACT Les différents niveaux archéologiques du site du Petit-Chasseur à Sion ont livré un tota... more ABSTRACT Les différents niveaux archéologiques du site du Petit-Chasseur à Sion ont livré un total de 583 charbons de bois répartis entre les niveaux Néolithique moyen I et Néolithique moyen II appartenant à la phase ancienne « Cortaillod type Petit-Chasseur ». Ces charbons sont principalement issus du bois utilisé comme combustible. Une petite part est également attribuée au bois d’architecture. L’analyse anthracologique du site du Petit-Chasseur est la première réalisée en Valais central en Suisse. Pour cette étude, deux axes ont été privilégiés : l’un, plutôt environnemental, propose un essai de restitution de la composition et des transformations des boisements proches du site ; l’autre, plus archéologique, aborde la gestion du bois à l’échelle du village pour la période du Cortaillod type Petit-Chasseur.
Sagvntvm Extra, Jan 12, 2011
This study evaluates the management of different sizes of firewood utilised in the Argaric settle... more This study evaluates the management of different sizes of firewood utilised in the Argaric settlement of Barranco de le Viuda (Lorca, Murcia). A dendrometric analysis was performed to estimate the radius of the curvature of growth rings in charcoal remains identified as Pinus halepensis. An analysis of two archaeological levels and two structures revealed that branches of a small calibre, mostly between two and five cm in diameter, were used. Fragments between five and fourteen cm were less abundant, and pieces larger than fourteen cm in diameter were found in only one of the structures. Treatment of the data by a mathematical model will allow the results to be corrected following certain parameters, such as the shrinkage caused by carbonisation or the error percentage associated with the measurement tool.
Bulletin de la Société préhistorique française, 2009
Bulletin de la Société préhistorique française, 2009
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution-NonCommercial-NoDerivatives| 4.0 International License Enfin des traces d'habitat à l'intérieur d'une enceinte du Néolithique récent du Centre-Ouest de la France: premiers résultats et perspectives des fouilles du site de Bellevue (Chenommet, Charente)
This paper proposes two correction factors designed to improve the accuracy of dendrometric tools... more This paper proposes two correction factors designed to improve the accuracy of dendrometric tools. The development of a referential framework on Pinus halepensis suggests that the “trigonometric tool” is the most appropriate technique for this estimation. The error rates associated with this tool are proposed as a first correction factor on archaeological measurements. The second correction factor is related to wood shrinkage. The percentage of radial and tangential shrinkage on P. halepensis sections is calculated. A test that applies this corrective factor on trigonometric measurements shows that tangential correction is more accurate than radial for treating archaeological data. Finally, an example of the application of both correction factors in the prehistoric site of Barranco de la Viuda is presented
Deschamps M., Costamagno S., Milcent P.-Y., Pétillon J.-M., Renard C. et Valdeyron N. (dir.) La conquête de la montagne : des premières occupations humaines à l’anthropisation du milieu, 2019
Au Néolithique, les montagnes sont exploitées pour leurs ressources minérales, cynégétiques et pa... more Au Néolithique, les montagnes sont exploitées pour leurs ressources minérales, cynégétiques et pastorales. À partir de 5 500 ans avant notre ère, les premières communautés agropastorales atteignent les Alpes depuis le nord de l’Italie et la vallée du Rhône et s’établissent dans les massifs subalpins comme dans les Alpes internes. Les études archéobotaniques (analyse des macrorestes végétaux, principalement des graines, des fruits et des charbons de bois) permettent de comprendre l’économie végétale de ces communautés néolithiques : quelles espèces, sauvages ou cultivées, étaient récoltées pour le fourrage, pour construire, se nourrir, se soigner, se chauffer ? Les données de cinq sites néolithiques nous indiquent les différentes façons dont ces populations ont exploité leur territoire en tirant profit des ressources de divers biotopes, de l’étage collinéen à l’étage alpin, contribuant ainsi à mieux comprendre la mobilité verticale au Néolithique en contexte alpin.