JCJC SHS 3 - JCJC : Sciences humaines et sociales : Cultures, arts, civilisations

Development of dendrometrical tools used in anthracology: study of the interactions between Man, resources and environments – DENDRAC

Population parameters and management of past forest stands

We develop analytical tools to address a variety of research problems, ranging from wood collections practices and techniques of use, patterns of forest management, techno-economic choices, their specific effect on the environment and ancient vegetation, or even the impact of climatic events.

Reconstruct the dendrometric characteristics of the tree and/or forest stand exploited

In archaeological sites, charcoal remains are an excellent marker of the environments frequented by man and of the plant formations that developed in these areas. As a residue of fire-wood selected and transported by man, charcoal also reflects techniques of forest management. Nevertheless, anthracological studies are most often limited to identification of a list of species and their relative frequency, without any use being made of the potential information contained in tree-rings. In doing so, these studies leave aside a wide range of applications relating to dendrology and dendroecology, involving both environmental and social sciences. Consequently, even the reconstruction from archaeological charcoal of the morphological characteristics of exploited wood (size, age, shape) still poses methodological problems. Yet this evidence is essential for examining modes of selection of wood for heating, for studying environmental, population parameters, as well as for measuring the impact of human populations on the forest. The principal objective of the project is to reconstruct the dendrometric characteristics of the tree and/or forest stand exploited, developing analytical tools adapted to wood charcoal fragments and allowing to determine the tree organ (trunk, branch), its age, and its growth form (diameter, coppice shoot, seedling tree). By developing this pioneer approach, the project seeks to increase the discipline’s informative potential concerning for example the modalities management of the forest space or the human and climatic impact on the environment. The production of such referential is a decisive methodological advance for charcoal analysis; these reference data will be dedicated to be diffused and completed (centralization, storage, durability and accessibility of data).

To reconstruct the dendrometric characteristics of the tree and/or forest stand exploited we are developing analytic protocols that combine tools from quantitative anatomy, geometric morphology, dendroecology, and isotopic study to highlight the discriminating anatomical criteria necessary for the identification of the organ of the tree, its age, and its physiognomy. These protocols aim to be compatible with routine use and are intended for archaeological wood charcoal whose size is not adequate for the application of traditional dendrochronological methods. Developed through the study of modern forested stands, our intention is to apply these protocols to anthracological assemblages that have been experimentally produced from these same forest populations. Because our principal objective is to be able to reliably quantify data related to simple parameters (such as the wood’s diameter and ring-widths), the testing is carried out under rigorously reproducible atmospheric conditions.

One of the main results obtained so far in the framework of the project is the testing of a new technique for measuring the radius of curvature of charcoal samples in order to reconstruct the diameter of the wood pieces. According to this technique the archaeological charcoal fragment is positioned virtually in relation to the pith that is most often missing. Two different tools were tested on seven taxa. The limits of validity were established and different factors of correction were suggested. A macro, free of charge, in order to calculate the radius according to trigonometric tools developed in collaboration with Nikon Instruments is today available. Another important result concerns the radial growth, an issue that had raised different questions. For example, is it possible to reconstruct the original growth conditions? Is it possible to detect conditions of stress? The first results seem to indicate that the use of tree ring width without taking into account the chronology, a common practice in charcoal analysis, is not relevant. Indeed the tree ring width has to be combined with age classes. In parallel, the development of a geometric morphometrical approach, in order to study the growing conditions of the original stand allows us to reconstruct the age classes. Very soon it should be thus possible to reconstruct to the initial growing conditions. Other important results are expected, especially concerning the quantification and modelling of diameter and radial growth parameters after carbonisation. Finally, a database has been elaborated in order to store and preserve the obtained data. It also meets the needs of adaptability of the project in terms of applications, of uses to be developed and of new research to be conducted.

Because one of the aims of the project is to develop a global referential, i.e. usable by everyone and not restricted to a particular research theme, we aim at developing a centralised system, accessible through Internet able to ensure the storage and sustainability of data. Thanks to a material and methodological supervision, the availability of protocols and measurement software (with updates, corrections, extensions) will allow the scientific community to exploit the proposed reference tables. This project is indeed thought in a way that others taxa than those presented here can be later added to the database. This approach will allow us to complete the anthracological referentials according to the zones of study and analysed taxa.

Concerning the study of wood diameters :
Dufraisse A. et Garcia-Martinez M.S. (2011). Mesurer les diamètres du bois de feu en anthracologie. Outils dendrométriques et interprétation des données. Anthropobotanica (2), p. 1-18.
Garcia et Dufraisse 2012. Correction factors on archaeological wood diameter estimation. In: E. Badal, Y. Carrion, E. Grau, M. Garcia , M. Ntinou (eds), Wood and charcoal : evidence for human and natural history. Saguntum extra 13, p. 283-290.

The questions raised by man-environment relationships through time and space can be explored by a variety of archaeological, ethnographic or environmental approaches. In archaeological sites, charcoal remains are an excellent marker of the environments frequented by man and of the plant formations that developed in these areas. As a residue of fire-wood selected and transported by man, charcoal also reflects techniques of forest management.
Nevertheless, anthracological studies are most often limited to identification of a list of species and their relative frequency, without any use being made of the potential information contained in tree-rings. In doing so, these studies leave aside a wide range of applications relating to dendrology and dendroecology, involving both environmental and social sciences. Consequently, even the reconstruction from archaeological charcoal of the morphological characteristics of exploited wood (size, age, shape) still poses methodological problems. Yet this evidence is essential for examining modes of selection of wood for heating, for studying environmental, population or climatic parameters, as well as for measuring the impact of human populations on the forest.
The main aim of the project is to develop a complete range of methodological tools, or anthracometric models, combining eco-anatomical, morphological (reconstruction of wood calibres) and dendro-ecological approaches applicable to charcoal assemblages in which fragment size is too small for classic dendrochronological work, since the number of rings is insufficient.
This project has a dual purpose 1) Elaborating, with the collaboration of ecologists, wood anatomists and dendrochronologists, a modern referential adapted to charcoal analysis with the help of both quantitative anatomy and geometrical morphometry techniques. The aim is to highlight the discriminating anatomical criteria (such as vessel size, ray heigth, ring curvature, tree-ring width, etc.) useful for the identification of some taxa (which are still now classified in groups and for which the analysis of the presence/absence of the anatomical criteria is not sufficient), of the exploited tree organ (trunk, branch), of the age, and of growth form (diameter, coppice shoot, seedling tree). 2) Putting into practice the referential (or anthracometric models) on charcoal assemblages experimentally recreated (in order to introduce the combustion vagaries) and trying to quantify the data on diameter and growth wood.
By developing this pioneer approach, the project seeks to increase the discipline's informative potential concerning for example the modalities management of the forest space or the human and climatic impact on the environment. As an exploratory purpose, a workgroup on stable carbon isotope analysis is proposed in order to quantify the d13C values in the different part of the tree (trunk/branch; heartwood/ sapwood; early wood/late wood).
The production of such referential is a decisive methodological advance for charcoal analysis; these reference data will be dedicated to be diffused and completed with the help of a website (centralization, storage, durability and accessibility of data).
The last phase will develop more specific models. The objective is to improve the tools in relation to specific research issues, then to test, adapt and validate them in an archaeological context. Examples here are the relationship between the anthracometric data (from firewood) and the dendro-typological evidence (from wood for building) in lakeside settlement contexts, or the consequences of burning in a charcoal-kiln on an anthracological assemblage. Further new fields of application will be tested, such as the distinction between gathered, dead wood and living wood, the study of tree pruning and pollarding techniques from archaeological charcoal, or the reconstruction of supply zones using present-day regional reference samples.

Project coordinator

Madame ALEXA2 DUFRAISSE2 (CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE ILE-DE-FRANCE SECTEUR EST) – dufraisse2@mnhn.fr

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CNRS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE ILE-DE-FRANCE SECTEUR EST
CNRS DR PARIS B CNRS DR PARIS B

Help of the ANR 130,000 euros
Beginning and duration of the scientific project: - 48 Months

Useful links

Explorez notre base de projets financés

 

 

ANR makes available its datasets on funded projects, click here to find more.

Sign up for the latest news:
Subscribe to our newsletter