In contrast to most Iron Age sites in Scotland, where only small amounts of charred plant remains are recovered, a wealth of information has been gained from the excavation of waterlogged deposits at Oakbank crannog, Loch Tay (Miller 1997), one of the oldest dated crannogs (Dickson and Dickson 2000).
The waterlogged deposits recovered from the site were found to contain a wealth of macroplant remains, both charred and uncarbonised, associated with daily activity. As with the excavations at Blackford (see Bronze Age section) the comprehensive sampling of deposits from the crannog site allowed detailed spatial analysis of the macroplant remains recovered and to assign categories to the plant remains indicating their potential uses on the site.
The main cereals cultivated were found to be emmer wheat and hulled barley, while grains of spelt wheat were also recovered. The recovery of spelt was at the time the earliest such finds for Scotland (Clapham and Scaife 1998; Miller 1997); it indicated that this wheat variety was being cultivated earlier in the Highlands of Scotland than previously thought. As emmer and spelt wheat require longer ripening periods, they are autumn sown and Miller et al (1998) argues that the inhabitants of the crannog must have planted their wheat crops in the autumn and the barley in spring. The majority of barley grown from the Late Bronze Age onwards in Scotland is the hulled variety (van der Veen 1992), which tolerates cooler, wetter growing conditions and is well suited to the Scottish weather. The introduction of hulled barley has been argued to be partly a result of a climatic shift towards increased rainfall and cooler, shorter, growing seasons during the Late Bronze Age to Early Iron Age periods (Jones 1981; van der Veen 1992; Dickson and Dickson 2000).
Spatial analysis of the macroplant assemblages from Oakbank allowed the identification of different household contexts within the dwelling: daily piecemeal processing of cereal ears for consumption (daily processing of stored crops); mixed hay and animal dung within floor deposits interpreted as fodder layers (a mix of hay fodder and cereal processing waste) and general occupation floor layers with little or no plant remains. Miller (1997) suggests that these indicated that specific areas within the dwelling were used for different functions, including food processing, sleeping, animal care and general living.
The well-preserved arable weed seed assemblage recovered at the site also provides some evidence on harvesting techniques. Hillman (1984) noted that the weed assemblage contained a large number of seeds from low lying taxa suggesting that the crops were being reaped low on the culm (stalk). While the remains of a wooden ard recovered from the site indicates that the cultivated soils were being tilled (Dixon 1984b); this gives us some insight to late prehistoric crop husbandry.
A high prevalence of wild plant remains, including seed fruits and nuts, were also recovered from the Oakbank samples, highlighting the continued importance of gathered foods throughout the prehistoric periods, including wild berries and hazelnuts. Of significance was the identification of cloudberry seeds (Rubus chamaemorus L.) at the site. Not only was this the earliest find of the berry in British prehistory (Miller et al 1997) but the plant has a very limited habitat restricted to areas of deep peat at altitudes above 700m and would not have grown locally around the crannog site. Its presence indicates that the inhabitants of the crannog travelled great distances from the dwelling to collect resources (Miller et al 1997). The berry is high in Vitamin C and it contains benzoic acid which means that the berries can be preserved by being crushed in their own juices and stored in a cool place without the need for added sugar (Wild berries: cloudberries’. Arctic Flavours Association. 2014).
Plant remains recovered from Roman deposits from the region are particularly rare, and the only Roman deposits that appear to have been sampled in Perth and Kinross is the waterlogged remains found at the Roman Fortress at Carpow (Dores and Wilkes 1999). Here, the sample from the inner ditch of the fortress was found to contain twigs, bark, heather flowers and cereal straw along with the seeds of chickweed, blinks, elderberry and pond weed. The pond weed suggesting that the ditch was filled with standing water.
