The environmental context and function of Burnt-Mounds: new studies of Irish Fulachtaí Fiadh

Burnt mounds, or fulachtaí fiadh as they are known in Ireland, are probably the most common prehistoric site type in Ireland and Britain. Typically Middle–Late Bronze Age in age (although both earlier and later examples are known), they are artefact-poor and rarely associated with settlements. The function of these sites has been much debated with the most commonly cited uses being for cooking, as steam baths or saunas, for brewing, tanning, or textile processing. A number of major infrastructural development schemes in Ireland in the years 2002–2007 revealed remarkable numbers of these mounds often associated with wood-lined troughs, many of which were extremely well-preserved. This afforded an opportunity to investigate them as landscape features using environmental techniques – specifically plant macrofossils and charcoal, pollen, beetles, and multi-element analyses. This paper summarises the results from eight sites from Ireland and compares them with burnt mound sites in Great Britain. The fulachtaí fiadh which are generally in clusters, are all groundwater-fed by springs, along floodplains and at the bases of slopes. The sites are associated with the clearance of wet woodland for fuel; most had evidence of nearby agriculture and all revealed low levels of grazing. Multi-element analysis at two sites revealed elevated heavy metal concentrations suggesting that off-site soil, ash or urine had been used in the trough. Overall the evidence suggests that the most likely function for these sites is textile production involving both cleaning and/or dyeing of wool and/or natural plant fibres and as a functionally related activity to hide cleaning and tanning. Whilst further research is clearly needed to confirm if fulachtaí fiadh are part of the ‘textile revolution’ we should also recognise their important role in the rapid deforestation of the wetter parts of primary woodland and the expansion of agriculture into marginal areas during the Irish and British Bronze Ages.