Contribution of tyloses quantification in earlywood oak vessels to archaeological charcoal analyses: Estimation of a minimum age and influences of physiological and environmental factors Alexa Dufraisse a, * , Sylvie Coubray a, c , Olivier Girardclos b , Aurore Dupin b , Michel Lemoine a a Sorbonne Universit es, CNRS, Mus eum National d’Histoire Naturelle, UMR 7209, Arch eozoologie, Arch eobotanique: Soci et es, Pratiques et Environnements, CP56, 55 Rue Buffon, 75005 Paris, France b CNRS, University of Bourgogne-Franche-Comt e, UMR 6249, Chrono-Environnement, 16 Route de Gray, 25030 Besançon Cedex, France c INRAP, Centre ^ Ile-de-France, 41 Rue Delizy, 93690 Pantin Cedex, France article info Article history: Received 14 June 2016 Received in revised form 31 January 2017 Accepted 31 March 2017 Available online xxx Keywords: Charcoal Dendro-anthracology Firewood exploitation Deciduous oak Heartwood formation Sapwood Tyloses abstract 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 e25-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. © 2017 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction The gathering of domestic firewood is a daily activity and de- pends on social and economic contexts (see for example Asouti and Austin, 2005; Picornell et al., 2011; Salavert and Dufraisse, 2014). Archaeological charcoals are a reflection of firewood gathering practices and woodland management, which are partially condi- tioned by the environment. However, the reconstruction of woodland management is still restricted as charcoal analysis is most often limited to the study of a list of taxa and their relative frequency without exploiting the dendrological information (i.e. woodland growth conditions) contained in the anatomy of the wood. Thus, practices of wood gathering and woodland manage- ment are often discussed even though direct evidence remains rare, in particular for Pre- and Protohistoric periods (Vernet, 1992; Thi ebault, 2002; Fiorentino and Magri, 2008; Badal et al., 2012; Damblon, 2013). In the 1990s, anthracology was enhanced by the development of image analysis techniques and new approaches based on wood anatomy. Charcoal identification, based on cellular structure, was associated with measurements of growth-ring width, charcoal-pith distances (i.e. the distance between the outmost ring boundary and the missing pith, see Dufraisse et al., accepted), size and number of vessels, etc. New characteristics of the collected woods and man- agement techniques are now discussed, such as woodland struc- ture and density, and competition dynamics (Marguerie and Hunot, * Corresponding author. E-mail address: alexa.dufraisse@mnhn.fr (A. Dufraisse). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint http://dx.doi.org/10.1016/j.quaint.2017.03.070 1040-6182/© 2017 Elsevier Ltd and INQUA. All rights reserved. Quaternary International xxx (2017) 1e8 Please cite this article in press as: Dufraisse, A., et al., Contribution of tyloses quantification in earlywood oak vessels to archaeological charcoal analyses: Estimation of a minimum age and influences of physiological and environmental factors, Quaternary International (2017), http:// dx.doi.org/10.1016/j.quaint.2017.03.070