Charcoal analysis of lime kiln remains in Southern France : an original process of mediaeval and modern traditional lime burning

摘要

In Southern France, little has been known concerning the techniques used for lime burning. Recent archaeological research (excavations and surveys) provides evidence of a new lime burning process using a little sole to shaft and high stokehole. These lime kiln elements have been recognized in sites such as Saint-Blaise-de-Bauzon (XIIIth century, Bollène, Vaucluse), earthenware factory Favier (XVIIth century, Montpellier, Hérault) and the Homme Mort Valley (XVIIth century, Peynier, Bouches-du-Rhône). These new archaeological data allow the re-evaluation of the development of this activity and associated firewood management. Several kilns have been excavated in the Lower Provence (France), especially in the high Arc Valley area, aiming at a better understanding of the links between kiln construction and architecture and fire control. A sampling protocol of charcoal has been defined, experimented and improved during excavation work. The careful excavation and sampling of the charcoal layers is followed by microtopography of the kiln in order to identify the morphology / pattern of the fireplace. Fine sieving (0,2 mm mesh) allows the recovery of even the smallest charred biological remains (twigs, spines, leafs) and the reconstruction of the technical process of supplying the fire with wood. Charcoal analysis has taken in account diverse factors. After the anatomical identification of the species, all the specimens have been calibrated; statistical results thus obtained testify to the use of kindling wood (from scrub vegetation). The bark is often preserved allowing us to identify the cutting season. Further charred botanical remains (leaves and spines) were studied in Montpellier (Institut de Botanique) and point to the use of a taper at the bottom of fireplace to light the fire, at the very begining of the burning. This process is well suited for a lime burning kiln provided with a high stokehole. This new conception of lime production leads to the re-interpretation of the results from old excavations all over the Northern-Western Mediterranean basin, especially in Tunisia and central Italy.