Lorna O'Donnell

The Iron Age in Ireland (700 BC-AD 400) has long been considered an enigmatic period, with a lack of archaeological evidence for everyday settlements. Given the recent explosion of archaeological excavations in Ireland due to the boom period of the Celtic Tiger years, it has now become possible to examine many aspects of daily life during this time. Woodlands were an integral resource during prehistory and one environmental method which has been under utilised in the study of Irish woodlands is archaeological charcoal analysis. In this study, charcoal is used to reconstruct past woodland environments from the Late Bronze and Iron Age in the south of Ireland. It potentially demonstrates a shift to wetter conditions during the Developed Iron Age. The first use model for fuel during the Iron Age is produced, indicating selection of species for certain activities such as smelting, construction and cremation, while trees were not specifically selected for domestic fires. Charcoal data indicates an increase in large tree cover, mainly oak, during the ‘Late Iron Age Lull’.

Swathes of roads and pipelines cut through the Irish landscape during the ‘Celtic Tiger’ years (approximately 1994–2008) leading to an unprecedented number of archaeological excavations and creating a unique opportunity for extensive research of past landscapes on a broad scale. The vast quantities of bulk soil samples suddenly available necessitated the development and adaptation of new methodologies. Despite the huge volumes of these samples, of which charcoal is the most ubiquitous ecofact, to date charcoal analysis has been considerably under-utilised in the study of past Irish woodlands. This research presents one of the largest Bronze Age archaeological charcoal datasets in Europe. It provides new palaeoecological evidence contributing to the understanding of woodland cover transformation on the island of Ireland during the late-Holocene period. The most common taxa identified in the charcoal assemblage compare well with regional pollen diagrams, particularly the use of Quercus and Corylus. With intensifying human activity during the middle Bronze Age, the proportion of Maloideae, a light demanding family rose. This is the first clear evidence of anthropogenic influence during the middle Bronze Age in Ireland derived from archaeological charcoal. The size of the charcoal dataset makes it possible to evaluate woodland cover and resourcing from two perspectives – both archaeological and palaeoecological.

The pyre was an integral part of the ritual of cremation, yet the actual wood that fuelled pyres has rarely been investigated from Bronze Age sites. This research examines environmental results focusing on charcoal data from the largest Bronze Age cremation cemetery discovered in Ireland.  A holistic approach combines charcoal, plant-macro, osteological and artefactual results to provide new insights into the cremation process in prehistory. It demonstrates that particular trees (oak, pomaceous fruitwood and ash) were selected over 600 years to fuel the cremation pyres at Templenoe, trends which are reflected regionally in both Ireland and Britain. Comparison of charcoal with osteological data suggests that the selection of wood did not reflect age or sex.  Pyre material was consistently buried with the cremated bones in graves indicating the importance of the pyre itself in the overall cremation process.  Empty funerary pits or possible “cenotaphs” contain the exact same wood taxa as the graves with bone, suggesting that it may be correct to interpret these as graves. It is possible that pyre material could have been buried as a proxy for the body.

An opportunity to investigate in advance of new construction led to the discovery of five Mesolithic hazel fish traps some 6.3m below mean sea level in the River Liffey. Closely paralleled on the continent of Europe they imply a well organised community that knew how to catch fish using the tide, to make wattle-work and baskets and who undertook coppicing on an eight year cycle in about 6100-5700 cal BC. The likelihood of more Mesolithic remains under European towns that have remained attractive to fishers and settlers has considerable implications for Cultural Resource Management. Do we always know how to find and access such delicate and important traces?

This research details the analysis of charcoal and charred plant remains from Knowth Site M, Co. Meath, Ireland. The site comprised a linear trench and cluster of irregular pits; a cemetery enclosed by two sub-circular ditches of 6th–10th century date; and an outer earthwork added sometime later in the early medieval period. Evidence for agricultural and manufacturing activity within the enclosures was also detected. This report concentrates on samples taken from ditch fills, post holes and pits that were excavated at the site.

This chapter discusses charcoal analysis from five sites dating from the Early Bronze Age to the Medieval period at Killeen Castle, Co. Meath. 34 samples were derived from various contexts including ditches, kiln and furnace fills, pits, fulachta fiadh-like material and charcoal spreads. 1158 charcoal fragments were analysed, with ten trees being identified.  Ash, oak and hazel are the most significant. A wider variety of taxa are present in the Early Medieval and Medieval contexts than the Early Bronze Age, indicating an opening of the landscape in later times. A mixture of dead decaying firewood with insect holes and fresh wood was used as fuel on each site. Oak was selected for metalworking in the area, which has many archaeological parallels.  In contrast, a wider variety of species were present in contexts associated with cereal-drying kilns. The charcoal from the early medieval and medieval period compares very well with other Irish woodland studies from the same time.

Reflectance is a method borrowed from coal studies which can estimate the absolute burn temperature of charcoals. Studies examining the usefulness of reflectance in archaeology are underway in a number of areas. This report details first results from reflectance testing of archaeological charcoals from known Irish Bronze Age cremations, which included calcinated bone. As calcination of bone occursat 650 °C to ≥  800 °C (Wahl, 1982), it was expected that the charcoals would reflect this temperature. This was not the case for identified charcoals > 2mm, nor for micro-charcoals of ca. 250 μ m. Cultural depositional modalities, combustion completeness and taphonomic influences may have all played a part in this result which suggests that the usefulness of reflectance will depend on depositional circumstances and charcoal collection strategies

WODAN is an integrated on-line wood and charcoal database that can be used for archaeological and biological studies and investigations in Ireland and beyond. It will serve both as a digital archive and a powerful tool for scientific research for environmental analysis both within Ireland and Internationally. For the first time, this database will allow specialists and non-specialists alike to search and query charcoal and wood results from excavations in Ireland and beyond. The development of an on-line database application is a fundamental departure from other environmental databases. It makes the catchment area of the database far greater than any previously designed environmental database.

At all times there will only be one, central, updated version available. It was designed with all known methods of charcoal and wood analysis in mind, in order to enable as many people as possible to use it. The database was developed in two stages. Firstly a prototype (alpha product), that served as a test bed for demonstration, amendment and refinement was developed. During this period, the team concentrated on implementing many advanced features that help to illustrate the capabilities of our approach. The second, or beta phase, involved stabilizing the system and ensuring that that overall user experience was successful. The development of the WODAN database and web application has all been carried out using free open source software. The content or data component of the WODAN resides in a MySQL relational database whose schema is based upon the standardised fields. The construction of the web interface to access the WODAN database is carried out using several components including Ruby on Rails (RoR), CSS and HTML.

Most commercial archaeological companies, universities and research institutions in Ireland are keen to use the WODAN database as a permanent digital archive of their wood and charcoal results from Irish excavations. Almost all specialists who have worked on Irish material are currently entering data into WODAN. 24 profiles have been created. Over 370 sites have been added, including approximately 1500 charcoal and 1000 wood samples. The scope for synthesis is immense. The database will be used as a springboard for environmental research. The wide ranging scope and nature of the data collection will mean that it will be possible to address important questions on the nature of woodland throughout Ireland’s history. Standardization of methods was one of the key aims of the WODAN project. This has been achieved through the development of database fields through numerous discussions and workshops. As a result, all specialists working in Ireland currently use the same recording sheets and methods. An international element has been added with wood and charcoal specialists from England, Belgium, Holland, France, Germany, Australia and America, all of whom have played an active role in the creation of the database.

The recent Celtic Tiger boom in Ireland resulted in a huge increase in housing and infrastructural developments throughout the country. In turn, this generated the highest number of archaeological excavations the country has ever seen. Road scheme and Gas Pipeline developments in particular provided the opportunity to examine a ribbon of sites, cutting a broad swathe through the landscape. These allowed the unprecedented chance to examine environmental material from a long, narrow line across the country, facilitating a landscape archaeology approach to interpreting charcoal results. One of these road improvement schemes (N8 Cashel to Mitchelstown) was taken by the author as a case study for a PhD, to use charcoal analysis to provide an insight into Bronze Age people's relationship and use of their available woodland.

The WODAN charcoal and wood database was launched in 2011, from INSTAR funding received from the Heritage Council in Ireland (Ref. grants 16679, 16705 and AR01042, 2008-2010). The WODAN project aimed to establish an online database for wood and charcoal from archaeological sites and to store published and unpublished literature (when accessible). The database itself may serve a multitude of purposes but first and foremost it is a digital archive. The datasets can facilitate scientific research as well as optimise future sampling strategies. WODAN helps to identify key research agendas for environmental archaeology. This will feed back to other aspects of archaeology, thus facilitating more fully integrated archaeological reports and unlocking data for interdisciplinary research. Another key aim is the national and international standardisation of archaeological wood and charcoal data.