Charcoal analysis from Iron age sites: a multi-scalar approach combining taxonomic identification, dendrology and taphonomy

Abstract Charcoal is the most common archaeobotanical remain recovered from the Iron Age archaeological contexts in the northwest of the Iberian Peninsula. This paper proposes a methodology that combines taxonomic identification together with the recording of dendrological and taphonomic attributes. The results obtained from six case studies– including on-site and off-site samples– dating between the 10th century bce and the 2nd century ce have provided multi-scalar information that can be analysed at the macro-scale (site), semi-micro scale (stage of site life-cycle), and micro-scale (functional context). This comprehensive methodology has extended the type and quality of archaeobotanical data provided by charcoal analysis, obtaining information not only about the management of woody resources, but also about aspects related to depositional and post-depositional alterations, combustion processes, plant growth conditions, and the presence of decayed wood in archaeological contexts. Our results show that samples collected from primary and secondary/tertiary contexts in Iron Age sites gave similar and complementary results. Data obtained from fire events showed percentages of charcoal vitrification and higher percentages of decayed wood. This study shows the importance of understanding the formation process of each individual context or even stratigraphic unit in order to adequately interpret the archaeobotanical data from it. Analysing anthracological data only at the site level is not informative enough to understand how wood resources were managed during their entire life-cycle, from the gathering of firewood or timber to its final disposal as debris.