Anthraco2015, du 30 août au 6 septembre, Fribourg

La 6ème rencontre internationale sur l’Anthracologie (anthraco2015), organisée par l’Université de Fribourg, sur le thème “Local to global significance of charcoal science“, s’est tenue à Fribourg du 30 août au 6 septembre 2015.

A cette occasion, Aurore Dupin (doctorante de la MSHE C.N. Ledoux en accueil au laboratoire de Chrono-Environnement) a présenté Anthracology of charcoal kilns in the forest of Chailluz (France) as a tool to understand Franche-Comté forestry from the 15th to the early 20th centuries.

Résumé de la communication: 
Franche-Comté (region of north-eastern France) was – at least since the 15th century – one of the French regions that produced the most charcoal. Demand was indeed high due to, inter alia, the consumption by the Saline of Salins, and, at a wider scale, by the metallurgy industry. In 1789, Franche-Comté even ranked second among French regions for the production of cast-iron and iron (Lassus, 1968). To assess the archaeological potential of the forests of Besançon (provincial capital of Franche-Comté since 1674), a LIDAR survey was carried out in the Chailluz Forest (north of Besançon) during the thesis of C. Fruchart. The surveys revealed about one thousand charcoal kilns distributed across 1700 ha. This high concentration of colliery platforms raised several questions. Did they work intensively over a short period, or during a longer period? Another major question concerns the presence of charcoal kilns in the ‘quart de reserve’, active from 1750 to 1969 (Dianin, 1995). Indeed, 25 charcoal kilns were radiocarbon-dated and revealed the first utilization of the platforms since the mid17th century to the early 20th century (Fruchart, 2014). Furthermore, the early 18th century was characterized by a scarcity of wood due to the increase of the population of Besançon by 100% in 70 years (Fohlen, 1965). Moreover, there was heavy demand for wood from forges, blast furnaces and the army. To alleviate this shortage, several large-scale felling of forested in the ‘quart de réserve’ was performed during the 18th century. Were charcoal kilns in Chailluz Forest used for this purpose, knowing that it had been forbidden to produce charcoal in this forest since 1763 (Dianin, 1995)? To further counteract this shortage, blast furnaces were prohibited in the area of Besançon, and Baume provided the firewood by flotation (Vion-Delphin, 1991). In light of this, what was the purpose of one thousand charcoal kilns? To answer these questions and understand the impact of charcoal production on the Chailluz Forest, we carried out an anthracological survey on nine charcoal kilns. A multidisciplinary approach (magnetic susceptibility, AMS dating, micromorphology) was applied to two platforms (CH29 and CH30) to establish a protocol for the study of the other charcoal kilns. We thus sampled the charcoal kilns by successive sections a few centimeters thick over a depth of 30 cm (thickness of the burnt soil) (Davasse, 2000; Py and Ancel, 2006 in particular). The charcoal concentrations (Paradis-Grenouillet, 2012) suggest that CH29 was used at least twice in 20 years. Also, we chose to study at least one platform by major type of forest stations (source: Organisation Nationale des Forêts). Preliminary results attest to the similarity between the anthracological spectra (hornbeam in majority, beech, linden, few oak) and the current forest stations. However, the presence of heliophilous species in the spectra (e.g. pome fruits, serviceberry, laburnum) suggests a more open landscape than nowadays. We identified 14 species in the anthracological spectra. By contrast, most other surveys identified only half a dozen of species (Rouaud, 2013, in particular). These results from the Chailluz Forest emphasize the diversity of the site. Finally, the absence in the spectra of some species currently present (such as Holly, English ash, elm) points to the presence of competitive forest products, other than charcoal.

Référence :

DUPIN A., GIRARDCLOS O., FRUCHART C., LAPLAIGE C., SORDOILLET D., DUFRAISSE A., NUNINGER L., GAUTHIER E., “Anthracology of charcoal kilns in the forest of Chailluz (France) as a tool to understand Franche-Comté forestry from the 15th to the early 20th centuries”, In LUDEMANN T. & NELLE O. (2015) : anthraco2015 – 6th International Anthraclogy Meeting, Congress Guide, abstract volume. – 145p. Freiburg i.Br. (ReproCenterUni Freiburg), 51.