Late Holocene history of woodland dynamics and wood use in an ancient mining area of the Pyrenees (Ariège, France)

Abstract

This paper focuses on past woodland changes and land uses in an ancient mining area of the Eastern Pyrenees (Ari ege, France). The area discussed is located at the western entrance of the Vicdessos, a valley with significant steel production, and it is crossed by the road used from the 14th c. to the end of the 18th c. for the iron-charcoal exchange with the forest Province of Couserans. The introduction of this singular exchange and the silver ore mining history of this border area raise the question of their impact on forest cover changes and changes in human practices and their link with anthropisation processes. To deal with this issue, we put in place an interdisciplinary approach involving archaeology, charcoal analysis, ecological history and geochemistry. The archaeological investigations and fourteen radiocarbon ages allowed characterising and dating of mining and charcoal-making remains. They situate the emergence of metal ore mining during the Second Iron Age and charcoal making activity between the 15th and 17th c. The geochemical analysis of 9 galena samples showed some different isotopic signatures between ores extracted in ancient times and those mined during the modern period. The charcoal analysis of (i) 2442 charcoals from 31 charcoal kilns (ii) 500 from one pedoarchaeological pit excavated in a waste heap related to firesetting, and (iii) 250 from two pedoanthracological sampling points carried out in the charcoal burning forest, permits a detailed reconstruction of the woodland cover changes from the Second Iron Age to the 19th c. Furthermore, the combination of data from different disciplines allows for a long-term reconstruction of human practices history and woodland management for different uses. In particular, the results show the transformation of the fir-beech forest, still dominated by fir around the turn of the Roman era, into pure beech wood managed on northern slopes for human daily needs, occasionally mining, lumber and mainly charcoal production until the 19th c. The elimination of fir dates back to the 17th c. This assumes the end of lumber activities in that period. Pedoanthracological and palynological data suggest that southern slopes, progressively deforested since the Bronze Age, were entirely devoted to permanent agropastoral activities probably at least since the end of the medieval period.

A study of late Holocene local vegetation dynamics and responses to land use changes in an ancient charcoal making woodland in the central Pyrenees (Ariège, France), using pedoanthracology

“…The relevance of using charcoal from both sources has been also demonstrated by another study carried out on an ancient mining area, Argentières, Aulus-les-bains, in the French Pyrenees, not far from our study area (Fig. 1b;Py-Saragaglia et al 2017). In this study, the small input of charcoal from kiln sites to soil charcoal found in pits is supported by their low charcoal content, close to that observed at the tree-line, and the proportions of main taxa that clearly differ between pedoanthracological pits and the nearest charcoal kilns.…”

“…(fir) are the most widely reported changes in the northern Pyrenees (Kenla 1977;Jalut 1984;Galop and Jalut 1994;Galop et al 2003). Since Gallo-Roman times (between the 1st century BC and the 4th-5th century AD), and especially from the end of the medieval period (ca AD 1500), mining and metallurgical processes are known to have caused further changes in woodland distribution, structure and composition (Camarero et al 1998;Davasse 2000;Dubois and Métailié 2001;Rius et al 2012;Py-Saragaglia et al 2017). But from these data, it remains difficult to accurately characterise these processes with high spatial resolution, which are very variable from one upper valley to another (Galop and Jalut 1994).…”

“…This discipline has been already used in the Pyrenees to study tree line variation (Cunill et al 2012(Cunill et al , 2013 and the creation of cultivation terraces in high mountain areas (Bal et al 2008). However, few soil charcoal studies have been done in the woodlands of the northern Pyrenees (Cunill et al 2015;Py-Saragaglia et al 2017). The aim of this work is to make a modest contribution towards improving this deficiency in the Vicdessos valley, a region otherwise well covered by previous palaeoecological studies.…”

“…This paper therefore provides evidence for the relevance of a pedoanthracological study carried out in a woodland formerly used for charcoal making. Due to the high risk of the transfer of materials from charcoal kiln terraces to soils, this context remains unusual for this discipline, but it has proved very interesting (Knapp et al 2013;Py-Saragaglia et al 2017). More specifically, by combining our results with other available palaeoecological and archaeological data, this paper aims to discuss 1, changes in the composition and structure of the tree cover since the mid Holocene, 2, fire events from natural or human sources, the type of burnt woodland and canopy openings, and 3, the age of the tree cover and its degree of maturity reached in the past.…”

Environmental effects of historical charcoal burning associated with water-powered ferrous metallurgy (Mała Panew basin, southern Poland)

“…Analysis of charcoal remains enables one to identify the tree species used for charcoal burning in order to study the exploitation of the forest and the impact of charcoal production on soil properties (e.g. Nelle 2003, Deforce et al 2013, Knapp et al 2015, Dupin et al 2017, Hazell et al 2017, Ludemann et al 2017, Py-Saragaglia et al 2017. Research on charcoal hearth remains and historical charcoal burning has also been carried out in Poland (Rutkiewicz et al 2019).…”