An Investigation of Vegetation and Environmental Change in the Comeragh Mountains

An investigation of vegetation and environmental change in the Comeragh Mountains

Dr Bettina Stefanini

An investigation of vegetation and environmental change in the Comeragh Mountains

Prepared by Dr Bettina Stefanini 8 Middle Mountjoy Street Phibsboro Dublin 7 Phone: 087 218 0048 email: [email protected]

February 2013

Introduction

Ireland has a dense network of over 475 palaeoecological records of Quaternary origin. However, there are few late-Holocene vegetation records from Waterford and the extant ones are truncated (Mitchell et al. 2013). Thus the county presents a blank canvas regarding prehistoric vegetation dynamics. Likewise, possible traces in the environment of its well documented 18th century mining and potential earlier mining history have not been found so far.

This study was commissioned by the Metal Links project, at the Copper Coast Geopark, which is part funded by the European Regional Development Fund (ERDF) through the Ireland Wales Programme 2007 - 2013 (Interreg 4A). It aims to investigate vegetation dynamics, mining history and environmental change in the Comeragh Mountains.

Site description and sampling

Ombrotrophic peat is the most promising medium for geochemical analysis since metal traces are thought to be immobile in this matrix (Mighall et al. 2009). Such deposits are equally well suited for microfossil analysis and for this reason the same cores were chosen for both analyses. The selection of potential study sites presented difficulties due to extensive local disturbance of peat sediments. Initial inspection of deposits on the flanks of the Comeragh Mountains revealed that past peat harvesting had removed or disturbed much of this material and thus rendered it unsuitable for analysis. A possible site in the central depression of the Com Tae corrie was rejected because sporadic inwash had produced bands of mineral material in the deposits. This material might potentially influence the geochemical profile and thus plans to investigate that site had to be abandoned. This left the deep blanket peat deposits of the central ridge of the Comeragh plateau. The mountains consist of Old Red Sandstone and are covered by largely intact blanket peat. However, there are quite extensive areas where the peat is eroding.

Two cores were extracted in September 2012. The first measured 0.72m and was taken in intact ombrotrophic blanket peat of total depth 2.12m at Irish Grid 228400, 108600 (S 284 086) and at ca 715m altitude using a Wardenaar peat cutter (Wardenaar 1987). The second site was an eroding peat bank or hagg ca 1km north-east of the first. Here a monolith measuring 1.75m was extracted from a total peat depth of 1.85m at Irish Grid 229200,109100 (S 291 091), Figure 1 and Figure 6.

Figure 1 Comeragh ridge, left, extraction of Wardenaar core in intact blanket peat. Middle and right, cutting of peat monolith from eroding peat bank.

Materials and methods

Pollen and microfossil extraction followed standard methods (Faegri and Iversen 1989). A Lycopodium spore tablet, batch number 177745 containing on average 18584 spores, was added to facilitate concentration calculations of the sample material (Stockmarr 1971). Samples were mounted in silicone oil and scanned at x400, x600 and x1000 magnification. At least 400 pollen grains and fern spores were identified for each sample. This excluded aquatics and local bog taxa. The aim here was to analyse a large and relatively stable pollen sum of non-local origin, that is, from habitats outside the local blanket bog and heath vegetation. However, grass and sedge pollen formed part of the 400 grain count, even though their origin is probably partly local. Pollen, spores and other microfossils were analysed along transects across each slide. Identification was based mainly on keys and image database material. Nomenclature followed Beug, Feeser and van Geel (Moore 1991; van Hoeve 1998; Beug 2004; Feeser 2009). Results were computed and displayed using the Tilia computer programme (Grimm 2011).

Results

Dating and peat accumulation

Three bulk samples, one from the Wardenaar core and two from the monolith, were prepared for AMS analysis which was carried out by the CHRONO centre, Queens University, Belfast. The resultant dates indicate that the peat started to form in the early Bronze Age at ca 4300 cal BP (2350 BC), Table 1 and Figure 2. From the age-depth relationship of these samples it appears that the shorter overall peat depth of the peat hagg may be due to water loss and shrinkage rather than to greater peat accumulation at the Wardenaar site. In the absence of more dates, the chronology is based on a simple linear interpolation model. This indicates that peat accumulation averaged 32 years cm-1 in the older section and 13.5 years cm-1 in the last millennium. More recent peat often has a faster accumulation rate than older sediments. This is due to the gradual

4 breakdown of peats as well as to compaction of older material. Dates in the text are quoted as calibrated before present (cal BP) where ‘present’ refers to 1950.

Depth UBA Lab AMS Cal BP (2 (cm) Core number 14C Age δ13C sigma) AD/BC 69 Wardenaar UBA-21270 950 ± 29 -27.7 921 – 979 AD 1038–1132 75 Monolith UBA-21271 1141 ± 25 -27.0 1116 – 1166 AD 874 – 946 162 Monolith UBA-21272 3569 ± 31 -30.1 3538 – 3600 1886–1968 BC

40 Wardenaar 60 Monolith 80

100 Depth (cm) (cm) Depth 120

140

160

180 -200 300 800 1300 1800 2300 2800 3300 3800 Calibrated years before present (present= 1950)

Figure 2 Age-depth relationship of the Wardenaar core and peat bank monolith based on three AMS dates and linear interpolation between these and the peat surface. The approximate location of the dated levels is marked with a star.

Geochemistry

The Wardenaar core was scanned by an ITRAX core scanner in the School of Geography, Planning and Environmental Policy, University College Dublin. This analysis would indicate the presence of geochemical traces which could have originated in mining pollution. The ITRAX scanner produces high resolution photo and x-ray images as well as x-ray fluorescence analysis (XRF) and profiles elements in the range of Al-U. Figure 3 shows the ITRAX output plot. From left to right this shows an optical image, X-ray, the count rate (kcps), the mean square error (MSE) and XRF plots of elements selected for their potential to indicate metal mining pollution signals. The scanner settings are shown below the plots. The MSE values show a consistent fit throughout the run. Copper content, Cu integrals, show little variation apart from where the counts, indicated by the kcps curve, drop. Their count rate is quite high, 500-600 counts per second, somewhat elevated compared with copper signals from minerogenic sediments. This may be due to the good sorption properties of peat (Turner, pers. comm.). The scanner did not detect any lead in the sample.

Calcium and iron show slightly elevated levels in the top of the core. This is possibly due to airborne dust deposition. The ‘Mo inc’ plot indicates that there was little change in water and carbon content throughout this core. The results do not indicate copper mining pollution in the Wardenaar core within the period of known mining activity in the region. However, the detection of the rather strong copper signal shows traces of this element in the core. The absence of metal mining pollution indicators may be a function of the large distance between the coring site and the mining locations. The Wardenaar coring site is located 18.5 km from Bunmahon. It may be worthwhile to investigate other sediments closer to known 19th century mining sites (Cowman 2006), to see if this could produce evidence for earlier mining. Alternatively it may be possible to provenance copper from the copper smelting finds that have turned up at Cootubbrid East in connection with the excavations of the Kilmacthomas realignment scheme (Fairburn 2008).

Figure 3 ITRAX plot showing from left to right photographic, X-ray, count rate, error, XRF plots of Cu, Pb, Zn, Fe, Mn and Cn count integrals as well as Compton scattering (Mo inc) and scan settings.

Microfossil analysis

The microfossils come from 17 samples, 8 from the Wardenaar core and 9 from older strata within the monolith. For a full list of the pollen and spore types identified in the samples, see Appendix A whereas a full list of non-pollen microfossils is tabulated in Appendix B.

By the time peat started to accumulate on the ridge local deforestation was already extensive. The deforestation removed the main pollen producers from the locality enlarging the ‘source area of

pollen’ (PSAs). At the onset of peat accumulation in the early Bronze Age much of the pollen may have come from a considerable distance from the core locations. Hence there is probably a substantial overlap between the PSAs of two sites. For convenience the microfossils are plotted and discussed as if they had come from the same core. This way of looking at them is also supported by the CONISS cluster analysis, Figure 4. This is based on the tree, herb and fern assemblages and shows major divisions between 40-50cm, between 155-165cm, between 10- 20cm, between 115-125cm and only the next largest division between 70-85cm. This latter division lies between the Wardenaar and the monolith cores. The diagram has been divided into zones A-F based on the CONISS divisions.

Trees and shrubs Herbs FernsCharcoal SCP - FLY ASHZone CONISS cluster analysis 0 10 COM - F 20 30 COM - E 40 500 50 60 COM - D 70 1000 80

90 1500

100 2000 COM - C

110 Depth (cm) Depth 120 2500

130 3000 140 Age (calibrated years before present) before years (calibrated Age COM - B 150 3500

160 COM - A 4000 20 40 60 80 100 20 40 20 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Increase in sum of squares Figure 4 Composite percentage diagram with zoning based on CONISS cluster analysis. The zones COM-A to COM-F are discussed in the text as Zones-A to F.

Trees Herbs - grassland Herbs - arable Ferns Bog and heath Indicator taxa

Alnus ALDERBetula BIRCHCorylus HAZEL FagusFraxinus BEECHPinus ASH PINE Quercus SalixOAK SorbusWILLOWUlmus ROWANApiaceae ELMAsteraceae CARROTLotusMatricaria CLOVERsubf. FAMILYPlantago Cichorioideae Poaceaelanceolata GRASS PLANTAINRanunculusRhinanthusRosaceae BUTTERCUPRubiaceae YELLOW Rumexundiff.Rumex RATTLEBEDSTRAW ROSE acetosaArtemisia acetosellaFAMILY BrassicaceaeSORREL FAMILY MUGWORTCannabaceae SHEEP'SChenopodium CABBAGEHordeum SORREL HOP/CANNABISTriticum GOOSEFOOTFAMILYBARLEYSecale WHEATAvena RYEFerns OAT FAMILYPteridium -perine Cyperaceae aquilinum BRACKEN SEDGESEricaceaePotentilla ERICASphagnum TORMENTIL FAMILYCalluna BOG HEATHERMOSS Type 10 CropophilousAssulinaGelasinospora fungiCharcoal T2 SCP - FLY ZonesASH 0 10 COM - F 20 30 COM - E 40 500 50 60 COM - D 70 1000 80

90 1500

100 2000 COM - C

Depth 110

120 2500 Age(yearscal BP)

130 3000 140 COM - B 150 3500

160 COM - A 4000 20 20 20 40 60 20 20 20 20 40 20 20 40 20 20 40 60 20 40 20 40 20

Figure 5, Percentage microfossil diagram of the combined cores, with CONISS pollen zones.

Zone – A, the oldest pollen zone only contains one sample. The sample is very different to the rest of the diagram as it is nearly entirely made up from arboreal or tree pollen. Corylus, Alnus, Ulmus, Quercus and Betula are the most common pollen types in this zone. Even so, the occurance of peat on the ridge, charcoal and Pteridium all indicate that openings in the woodland were present at this time. The Calluna pollen fraction is still small at 12%.

Zone – B, shows at first a gradual and later a pronounced rise in Poaceae and Plantago lanceolata as well as other grassland species and some pollen types indicative of disturbed ground. The open- ground taxa increase and the tree pollen fall to 31% at 135cm. This combines with a rise in Coprophilous fungi, charcoal and Gelasinospora.

Zone – C, the largest pollen zone starts out with an increase in arboreal pollen particularly Corylus, Alnus, Fraxinus, Salix and Ulmus and to a lesser extent Quercus. The maximum increase in tree taxa at 115cm is mirrored by a decrease in Pteridium, Cyperaceae and Coprophilous fungi. Poaceae, which had made up a quarter of the pollen sum in Zone – B, dip to just over 10%. Many of the meadow herbs disappear for the time being. This level shows high Type 10 values and the sediment also contained one egg case of the whipworm Trichuris. This measured 17 by 35µm and was thus smaller than the average human whipworm egg case and more likely to have come from an animal (Da Rocha et al., 2006). The situation temporarily reverses at 105cm but subsequently open ground taxa decline substantially towards the end of the zone. However, at the same level of 85cm the first farming indicator, a grain of Hordeum, is present. The zone ends with a decline in Corylus and with a concurrent increase in Alnus, Betula, Fraxinus and Quercus as well as Poaceae, Plantago lanceolata, Pteridium and Cyperaceae.

Zone – D, and the start of the Wardenaar core is characterised by a rise in all arboreal taxa bar Corylus. The latter shows a decline from 63% to 27% at 70cm. At the same time grassland pollen types increase. This is particularly the case with Poaceae, Plantago lanceolata, Rumex acetosa and R acetosella. Pteridium, Cyperaceae and Coprophilous fungi also increase while microscopic charcoal appears at a larger scale in this core. The top of the zone shows the disturbed ground and cultivation indicators Artemisia, Hordeum and Secale.

Zone – E, here a sharp decline in all arboreal pollen taxa is followed by the appearance of non- native Fagus and Pinus. All grassland taxa increase to their highest levels in the record. Disturbed ground and arable agriculture-indicating taxa become common with Triticum and Avena joining Hordeum and Secale among the cereals.

Zone – F, the top of the core shows a decline in meadow herbs like Poaceae and Plantago lanceolata as well as in the arable indicator curves. This produces an apparent increase in tree taxa. However, the concentration diagram (not shown) indicates that apart from Pinus, tree pollen values also decline. Instead, coprophilous fungal spores become more important and Spheroidal Carbonaceous Particles (SCPs) or fly-ash, become common.

Discussion

Zone A, 4000 to 3800 cal BP (2050 to 1850 BC)

The single sample in this zone comes from 165cm. The peat extended somewhat deeper than this level, thus the chronology can be projected to the bedrock. This provides a date of approximately 4300 cal BP (2350 BC) for initial peat growth on the Comeragh ridge. The date compares quite closely with other Irish upland sites and dated pine stumps from Wicklow. One of these, which was growing between the mineral substrate and the bottom of the blanket peat near Glencree at 630m altitude, was dated to 4725 ± 97 cal BP (Haakansson 1974). Peat profiles show that blanket bog initiation at Irish upland sites tends to fall into the period between ca 5500 and 3500 cal BP (3550 to 1550BC) with dates centring around ca 4200 cal BP (Bradshaw and McGee 1988; Francis 1987; Goddard 1971; Holland 1975; Pilcher 1973). Prior to the start of high altitude blanket bog growth, most pollen records from Irish upland lake sediments already show changes consistent with anthropogenic land use. For instance in the Wicklow uplands at Art’s Lough and Kelly’s Lough, altitude 490m and 585m respectively, an initial expansion of grass and plantain took place at the same time as the heather pollen curve started to expand. Forest tree pollen declined synchronously at ca 6000 and 5500 cal years BP (4050 and 3550 BC) and hence not long after farming was first introduced into Ireland, ca 4000 BC (Bradshaw and McGee 1988; Leira et al. 2007). If the Wicklow model holds for the Comeragh Mountains, it can be assumed that the ridge was originally covered by forests but that this cover was lost between 6000 and 4000 cal years BP (4050 and 2050 BC). Eventually the soils that had been held together by the roots of the trees eroded. This may have lead to the bare ridge of the Comeragh Mountains looking something like the top of Errigal or the Sugarloaf Mountain look today. This model has yet to be tested locally, for instance through pollen analysis of a core from one of the corries.

By the time the record opens, blanket peat had started to grow and presumably covered most of the ridge. Since few trees can grow in peat, the substantial tree pollen percentage of the earliest sample must have originated on the mountain slopes and in the lowlands. The majority of the herb and grass pollen is also assumed to be non-local to the coring site, although there are likely exceptions. For instance some of the sedges and grasses recorded may well have grown locally. Pine, which was once widespread in Ireland, had disappeared from many areas before the period covered by this record. There are few pollen records from the south-east and hence little evidence for the date of its disappearance in Waterford. The closest records to the coring site, those from Woodstown and Newrath, show that pine disappeared here early, maybe sometime around 5500 cal BP (3550 BC) (Farrell and Coxon 2004; Timpany 2009) . The very small percentage of pine in this sample probably originates from further away and has been transported from regional or extra-regional locations.

Even though the local landscape at this time is a product of previous deforestation episodes, not many open-land indicators show up in this sample. One exception is a small quantity of angular microscopic charcoal fragments indicating wood fires. Another one the beginning of the bracken spore curve which shows that the woodland contained some openings. Bracken is one of the few plants able to grow under light woodland canopy and also in the open. But spore production and

10 dispersal increase manifold when the fern grows in the open. Thus the appearance of its spores is a good indicator of woodland openings and clearance.

Intriguingly an extensive complex of ritual and settlement sites is located ca 5km south-west of the coring site in the upper Araglin valley. The complex was occupied in the early Bronze Age (Moore 1995). The complex has not been excavated and its date appears to be based on the typology of the monuments. Hence the assumption that it dates to just before the opening of the vegetation record, can’t be tested. The extent and type of the cluster of monuments is quite unique in Ireland. The monuments cover an area of 3km length and 1km width and lie between 200-300m altitude, Figure 6. Moore postulates that the activity at these sites is likely to have taken place over at least a 500 year period with settlement evidence in the form of 23 hut sites postdating the ritual monuments of cairnfields and cemeteries.

A Beaker Period house (ca 2400-2200 BC), located 10km south-east of the coring site, was excavated in conjunction with the construction of the N25 Kilmacthomas realignment scheme. The excavation of the house produced remains of barley and wheat, which date to approximately the same time as peat initiation on the ridge (Brewer 2008).

Further evidence for widespread prehistoric human presence locally comes from numerous fulachta fiadh, cairns and standing stones listed in the Sites and Monuments Record (SMR).The location of mostly Bronze Age but also other prehistoric and later archaeological sites and their spatial relationships to the coring sites are mapped in Figure 6.

The distance between the monuments and the coring sites, as well as dating uncertainty of the archaeology and the pollen core, make it impossible to correlate the two records. Nevertheless the sheer number of monuments dating to approximately the same period as peat initiation and later woodland clearance amounts to circumstantial evidence for increasing human agency in land-use change during this period.

Monolith at ca 717m altitude, peat hagg Wardenaar core at ca 715m, intact blanket peat Archaeological sites in the SMR Figure 6 shows the location of the Bronze Age complex of the upper Araglin valley and other archaeological sites recorded in the SMR and their relationship to the coring locations. (Data copyright of NMS and OSI)

Zone B, 3800 to 2850 cal BP (1850 to 900BC)

The pollen shows the first large-scale vegetation change and increasing agricultural expansion in this zone. Due to the number of undated monuments and to the low dating resolution of the pollen cores, it is difficult to correlate the vegetation and archaeological records. Nevertheless, it is likely that both strands of evidence point to concentrated activity in the area during the mid and late Bronze Age. In the vegetation record human land-use pressure culminates at 3000 cal BP (1050 BC).

It manifests itself in a substantial decrease in elm, hazel and alder pollen, maybe suggesting that trees were increasingly cleared from the slopes or other nearby locations. Birch and oak percentages do not show much change. Their constant pollen percentage could point to a larger distance between the pollen producing trees and the coring site.

Among the herbs, grass, plantain and some meadow species increase. Plantain in particular is interpreted as a pastoral farming or herding indicator because it tends to grow in locations like fields and paths where trampling is common. Animal husbandry is underlined by a smattering of coprophilous fungal spores. In contrast to the tree and herb pollen, coprophilous fungal spores are thought to deposit close to their place of origin. This is because the fruiting bodies of the fungi, which grow on the dung of grazing animals, are located very close to the ground surface. This makes dispersal over long distances less likely (Feeser 2009). Hence animal husbandry is shown both by grassland indicators, presumably originating in the foothills and lowlands, and by some local grazing on the ridge. There is evidence for disturbed ground but no cereal pollen at these levels. This is not necessarily surprising since cereals produce very large and heavy pollen grains which do not disperse well. Further evidence for human influence comes from the growing bracken

12 curve and an increase in microscopic charcoal. Gelasinospora values are high in this zone, indicating that conditions were relatively dry on the ridge.

Zone C 2850 to 1100 cal BP (900 BC to AD 850)

The beginning of the zone shows a recovery of tree species, particularly hazel, alder, ash and willow. Alongside the increase in arboreal pollen, pastoral and cultivation indicators diminish. A reduction in the bracken, dung fungi and charcoal curves also shows diminished human activity in the area. Agricultural indicators are lowest at the very end of the Bronze Age and the beginning of the Iron Age from ca 2650 cal BP (700 BC) to ca 2350 cal BP (400 BC) but increase again by 2020 cal BP (70 BC). At this point coprophilous fungi and the microscopic charcoal curves are high and the testate Assulina indicates wet conditions. After this point many of the anthropogenic indicators, such as plantain, bracken and charcoal, contract. Among the trees and shrubs hazel expands to its highest value of the record. A reduction in farming indicators is a common feature of Irish pollen records of the late Iron Age (Mitchell and Ryan 1997). This correlates closely with the archaeological record which also shows much reduced activity through this period (Raftery 1994). In Waterford specifically, very little Iron Age archaeology has been identified (Johnston et al. 2008; Moore 1999). If anything, the effect of the late Iron Age lull is less pronounced in the Comeragh pollen record than is usual. For instance the grass curve does not drop here until 1350 (ca AD 550). A similar feature is present in the Wicklow uplands where the two records of Kelly’s and Art’s Lough also fail to indicate a substantial reduction in grasses and where there is little increase in tree pollen at this time (Leira et al. 2007; Bradshaw and McGee 1988). The absence of a pronounced late Iron Age lull in all of these upland pollen records might be due to previous degradation in these ecologically fragile uplands. Unsustainable land-use practices during the Bronze Age and in the early Iron Age may have lead to leaching and nutrient depletion pushing these areas across a tipping point whereby the soils became too degraded and acidic to support anything other than a heath or poor grassland communities. The last sample of the zone marks the start of the early medieval period at 1350 cal BP (ca AD 600). There are still very few agricultural indicators present in this horizon apart from the first cereal pollen grain of the record. This is a single grain of barley. Single pollen grains shouldn’t be taken as evidence of local presence of the vegetation type since the background pollen fraction can be large and some of it may have travelled over long distances. However, the archaeological evidence for early medieval settlement and farming appears quite suddenly in Ireland after AD 400 and is particularly rich (Kerr et al. 2010). Thus the appearance of cereal pollen in this horizon does not surprise.

Zone D - 1100 to 530 cal BP (AD 850 to AD 1420)

This zone marks the break to the Wardenaar core. Regrettably there is a larger gap between adjacent samples at this point and much of the early medieval period remains unrecorded. The next sample dates to 900 cal BP (AD 1050). This is an interesting horizon in that it shows a large increase in birch, oak, alder and ash – all light dependent trees - and hence particularly good colonisers of open landscapes. This suggests that anthropogenic pressure on the land has eased. An alternative explanation could be woodland management and hazel clearance which favoured other trees.

The archaeological and historical records are particularly rich during this period. The ecclesiastical foundations of Lismore and Ardmore as well as the abbeys of Mothel and Molana became very important in the county and ringforts are recorded in the foothills and lowlands of the Comeragh and the Mullveagh Mountains (Moore 1992; 1999). The end of the zone shows a marked decline in tree species and an increase in pastoral and arable agriculture indicators. The latter produces another pollen grain of barley and one of rye. Very few sites with cereal assemblages from Co Waterford and this period have been excavated (Bennett 2009). Where cereals from early medieval contexts were identified in Munster, oats were by far the most common types found. Barley was also common while wheat and rye appeared more occasionally (Monk et al. 1998; Monk 1985).

The CONISS clustering did not indicate a very major difference in the pollen of the two cores. However, these divisions are based on tree, herb and fern pollen only and it is difficult to say whether the substantial increase in charcoal is a function of the different coring site. Alternatively it might show charcoal pits and fuel production in the uplands to produce the substantial amount of fuel that was needed to supply the growing towns, to be used in metal working and to operate corn drying kilns (Johnston et al., 2008; Kerr et al. 2010; Monk et al., 2005).

Figure 7, Spore and pollen taxa. From left to right bracken, barley, rowan, oak and plantain. The photos are not on the same scale.

Zone E, 550 to 150 cal BP (ca AD 1400 to 1800)

The pollen from this zone portrays a landscape dominated by agricultural expansion with a near total drop in tree pollen. Most of the large Irish forests which had survived the medieval period were cut down in the wake of the Cromwellian wars. Many woodlands were cleared for tactical reasons to take away the base where Irish rebels could hide. Others were exploited for energy hungry industries like charcoal burning, glass and vat making, metal working and shipbuilding (McCracken 1971). McCracken compiled an inventory of the state of Irish woodlands around 1600 (McCracken 1959). She cites the Civil Survey, which reports that Sir Charles Vavasour brought his army through Barnakill Gap between the Cumeragh and the Monavullagh Mountains. They marched through woods of oak, ash and birch in 1643. The sample dated closest to this period does not show much pollen from these trees. However, the bottom of this zone may be somewhat younger than indicated by its chronology. This is because accumulation rates in the top sections of cores are almost always faster. Once below the water table peat breakdown rates become much slower.

Apart from these early clearances, remaining scrub and secondary woodland were largely cleared for fuel by a rapidly growing population. The population of Munster nearly quadrupled in a little over a century. It expanded from 630,000 in 1712 to 2,400,000 in 1841 (Graham and Proudfoot 1993).

Alongside the decline of arboreal taxa, agricultural indicators increase, particularly plantain, grasses, herbs and plants of disturbed ground, which indicate arable agriculture. Cereals feature more prominently in the pollen record and agree with plant macrofossil evidence which shows an increase in arable production around this time (McClatchie 2007). The cereals recovered from a pit near Kilmacthomas showed 83% oats, 12% barley and only 9% wheat (Brewer, 2008).

The rapidly increasing pine and beech pollen curves indicate the plantation of these exotic species in the last centuries. The remains of Assulina point towards increased wetness on the ridge in this period which corresponds to the little Ice Age.

Zone F - 150 cal BP to present (ca AD 1800 to 2012)

The top zone suggests a large change in land-use. Here, many of the traditional herbs that indicated agriculture earlier are missing. They disappeared together with traditional hay meadows and farming methods, which were heavily dependent on manual labour. Concentration calculations indicate that there is much less pollen overall in these levels. This reduction makes it appear as if there were an increase in tree pollen. However, this is just an artefact of the stark decrease in plantain and grass pollen in the percentage drawing. Spheroidal Carbonaceous Particles (SCPs) or fly-ash shows the use of fossil fuels, probably initially mainly peat (Rose 1999). Tree cover had reduced to 1.4% by the turn of the 20th century (Neeson 1991). Due to plantation forests it has recently increased to about 10%.

Conclusions

The Comeragh vegetation record shows clear linkages to other Irish upland sites in the timing of initial blanket peat development on the ridge at ca 2350 BC. In contrast to many other upland areas, the Comeragh record is closely linked to local archaeological and historical settlement history. The archaeology of the mountain slopes and of the upper Araglin valley is mostly of early Bronze Age origin and may predate the record. But activity connected to settlements of that time contributed to openings in the local woodlands visible at the start of the record and to initial blanket peat and heath formation in the uplands. Bronze Age tree clearance phases and agricultural indicators relate to extensive local settlement in the vicinity of the coring sites. In the late Bronze Age and during the Iron Age, woodland regeneration is less vigorous than might be expected. This may be due to earlier environmental degradation of relatively fragile upland soils. Dung fungi show sporadic upland grazing through periods when the pollen record indicates more intense land-use. The last large forest said to have grown on the Comeragh plateau in 1643 may

15 correspond to a pollen strata dated to somewhat earlier than indicated in the current chronology. Non Pollen Palynomorphs (NPPs) imply dry environmental conditions on the ridge between 1850 and 900 BC, between 750 and 400 BC and again at AD 600. It may have been wetter around 100 BC and also in more recent centuries corresponding to the Little Ice Age.

According to the ITRAX scan of the Wardenaar core the geochemical signal does not show much metal air pollution during the last millennium. In particular there appears to be an absence of peaks that might be related to known eighteen century mining activities. The most likely reason for this absence is the great distance between the core location and the mining sites. Peat deposits form an ideal matrix to investigate past metal mining pollution because minerals appear to be largely immobilised in these sediments. However, in the absence of suitable peat deposits closer to the mine sites, a reassessment of a possible investigation of the lake sediments of Ballinlough should be carried out.

Acknowledgements

The author would like to thank the following for their help with fieldwork, geochemical analysis and advice in compiling this report: Joe Greene, Willie Warren, Randal McGuckin, Jonathan Turner and Eileen Reilly.

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Appendix A

Pollen counts

Depth (cm) 5 10 20 30 40 50 60 70 85 95 105 115 125 135 145 155 165 Pollen taxon Alisma 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Alnus 13 9 5 7 28 38 42 67 34 39 22 39 49 19 62 61 82 Apiaceae 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Artemisia 0 2 0 2 3 2 4 0 0 0 0 0 0 1 0 0 0 Avena 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Betula 14 14 4 11 40 31 30 74 17 13 27 20 17 12 14 14 13 Berula erecta 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 Brassicaceae 1 1 2 1 0 1 1 1 0 0 0 0 0 1 0 0 0 Calluna 162 421 247 74 356 95 164 163 92 191 333 176 266 99 203 181 56 Campanulaceae 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 Cannabaceae 0 0 0 0 1 0 0 0 0 3 1 0 0 0 1 0 0 Centaurea jacea 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Cerealia undiff. 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Chenopodium undiff. 0 0 1 0 0 0 0 2 0 0 0 0 0 0 1 0 0 Asteraceae subf. Cichorioideae undiff. 1 0 2 1 1 1 0 0 0 0 1 1 0 3 1 0 0 Corylus 28 24 9 19 55 103 121 114 213 150 147 222 163 50 166 174 228 Cyperaceae 31 62 62 157 44 72 28 13 3 11 47 19 15 40 7 1 5 Empetrum 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 Ericaceae 6 15 4 1 6 0 1 1 7 1 6 7 0 3 2 2 0 Fagus 2 3 3 1 1 1 0 1 0 0 0 0 0 0 0 0 0 Filicopsida (monolete) 2 1 2 5 3 5 1 1 1 1 2 4 2 1 2 4 2 Filipendula 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Fraxinus 7 6 8 1 4 3 4 7 3 18 3 9 6 1 2 0 1 Galeopsis Balota-type 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 Hedera helix 2 1 0 0 0 0 2 2 0 0 0 0 0 0 0 0 0 Hordeum 0 0 0 1 0 2 0 0 1 0 0 0 0 0 0 0 0 Hypericum elodes 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Ilex aquifolium 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 2 Juniperus 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 Lamnium 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 Lemna 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Lotus 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Lycopodium 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0

Matricaria 2 3 2 6 2 4 0 0 0 0 1 0 0 0 0 0 4 Myrica gale 0 0 0 0 0 1 0 0 1 0 0 1 0 0 0 1 1 Myriophyllum 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 Papaver rhoeas-type 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Picea 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Pinus 79 56 26 1 1 0 1 0 1 0 0 1 0 1 1 1 9 Plantago lanceolata 12 15 86 35 62 12 29 10 3 3 23 9 10 29 19 8 0 Plantago maritima 0 0 2 2 0 0 0 0 0 0 0 1 1 1 2 0 0 Plantago major/P. media-type 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 Poaceae 140 125 178 94 131 55 48 54 16 62 69 49 67 84 51 54 0 Polygonum aviculare 1 0 0 2 0 1 1 0 0 0 0 0 0 0 0 0 0 Polypodium vulgare 2 0 0 0 1 1 0 1 0 6 1 3 0 2 1 8 1 Potentilla 0 0 2 1 1 4 1 2 0 1 0 3 3 0 1 0 0 Pteridium aquilinum 13 10 27 80 53 40 30 20 12 0 41 6 19 67 37 30 1 Quercus 7 3 5 5 11 32 43 32 19 18 19 25 31 18 30 30 26 Ranunculus 6 1 2 3 2 2 4 5 6 3 2 8 7 4 8 0 2 Rhinanthus 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Rosaceae undiff. 1 3 2 0 1 1 4 0 1 1 2 0 0 0 1 0 0 Rubiaceae 0 0 1 0 4 0 0 1 0 0 0 0 0 1 0 0 0 Rumex acetosa 4 0 3 2 3 7 2 0 0 0 0 0 0 0 1 0 0 Rumex acetosella 0 5 4 2 1 2 3 2 0 0 0 2 0 2 0 0 0 Rhynchospora 2 0 0 1 0 1 2 0 0 0 1 0 1 0 0 0 0 Salix 2 0 0 2 0 0 2 1 0 1 1 3 1 3 0 0 0 Saxifraga 0 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 Secale cereale 0 0 1 0 2 1 0 0 0 0 0 0 0 0 0 0 0 Silene 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Sorbus 1 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 Sphagnum 30 2 19 121 129 26 31 19 25 1 23 1 18 9 4 22 5 Tilia 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 Triticum 2 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Viola 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Ulmus 2 3 2 0 4 0 2 1 0 9 3 6 4 2 2 12 22 Urtica 1 1 0 1 0 0 0 0 1 1 0 0 0 0 0 0 0

Appendix B

Non Pollen Palynomorphs

Depth (cm) 5 10 20 30 40 50 60 70 85 95 105 115 125 135 145 155 165 Indicator taxon Type 8E 2 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 Type 10 3 17 68 30 116 21 39 52 119 37 102 310 290 67 0 1 0 Type 55A 0 1 0 0 0 0 0 0 0 2 4 0 0 0 0 1 0 Type 125 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 Type 205 0 0 0 1 1 0 1 1 0 0 0 0 0 0 0 0 0 Type 234 0 0 0 0 0 0 0 0 0 0 0 10 2 0 0 0 0 Type 466 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 Type 494 0 0 0 0 2 1 1 5 0 6 1 3 1 0 0 0 0 Meliola niessleana 0 1 15 3 15 9 22 8 2 13 25 1 2 0 0 0 0 Assulina 0 18 4 0 1 1 2 0 0 0 2 0 0 0 0 0 0 Pediastrum 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Gelasinospora T2 0 1 0 1 0 0 0 0 1 0 0 0 3 3 10 5 0 Type BRN7 Schizothecium 0 3 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 Type BRN3 unknown Conidia 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Helicoon pleuriseptatum 70 16 3 0 0 1 1 0 0 0 0 0 0 0 0 1 0 Trichuris 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 Charcoal 60 65 62 109 196 227 270 226 33 60 96 26 58 33 121 36 15