Dendro-anthracology of Pinus halepensis Miller in prehistoric and protohistoric Mallorca (Balearic Islands, Western Mediterranean)
Résumé
In this paper we present the results of the dendro-anthracological analysis of Aleppo pine (Pinus halepensis Miller) charcoal fragments from different prehistoric and protohistoric sites in Mallorca (Balearic Islands). We have analysed charcoal fragments recovered from 5 different contexts in 3 archaeological sites of the island dating from the Late Bonze Age to the Late Iron Age. Aleppo pine trees are present in Mallorca’s woodlands since the early Holocene and at the moment of the human population of the archipelago (Burjachs et al. 2017). Pine is documented in the anthracological analysis of prehistoric sites from the earliest analysed samples, but anthracological data show that it is specifically targeted exploited during the Late Iron Age. Our aim is to further interrogate pinewood exploitation during these periods and evaluate potential variations of its management strategies. Our methodology involves the systematic measurement of 2 different features on archaeological charcoal fragments of Aleppo pine: the charcoal-pith distance and ring width.
Charcoal-pith distance is measured with the trigonometric pith location tool, based on measurements of the angle and the distance between 2 rays observed on the last preserved ring of each fragment. The data offer an estimation of the wood diameters exploited in the past, expressed in diameter classes (Dufraisse et al. 2018). This information is complemented by the measurement of the ring width of all the complete rings preserved for each fragment. The combination of both dendro-anthracological parameters (diameter class and ring width) permits the organization of the results on different anthraco-typological categories referring to both diameter (small wood and/or internal part of mature wood) and growing conditions (fast/slow growth) of the Aleppo pine trees. This information has been compared with the results of the analysis of the ring width and growing conditions of trees in 3 different contemporary forest formations in Mallorca representing the environmental variability of the Aleppo pine forests on the island. In each station 5 trees were sampled, obtaining 2 cores of the trunk and 3-4 branches of different diameter, allowing the comparison of the annual growth on both trunk and branch wood of the same tree for the same cambial age. The results permit interrogating different exploitation modes of pinewood, referring to firewood and/or timber procurement, the growth conditions of the Aleppo pine woodlands, and the overall management strategies of this important Mediterranean arboreal species in the past.