2.4 Plant macrofossils and charcoal

Figure 10
Figure 10: Composition of charcoal remains from floor of medieval building (layer 27027) (Clickable image) [Download full size image]

A full account of the botanical samples from the site is presented in the assessment report (Cotswold Archaeology 2016, appendix 9), which also contains the methodology employed in the analysis. This updated report focuses specifically on the remains from the medieval building in Area 2, where further work on identifications of the charcoal and other plant remains and their spatial distribution has contributed to our understanding of the building's structure and its contents at the time it was destroyed. All the botanical identifications are to be found in data tables (charcoal [CH] and charred plant remains [CPR]) (Download as .xlsx). Charts have also been created from selected samples discussed here (see Figure 10 and Figure 12)

Data: Charcoal [CH] (Download as [.xlsx])

Data: Charred plant remains [CPR] (Download as [.xlsx])

The floor and associated features and deposits of the building had been partly sealed by a layer of burnt material (27027) containing the remains of large burnt timbers 27139, 27140, 27141 and 27138, suggesting a catastrophic burning event had occurred. In order to gain as much information as possible about the building, deposit 27027 was sampled spatially, using 1m² grid squares (Figure 10). Soil Samples [SS] were also recovered from beam-slot P, internal pits, postholes and oven features, along with pit 27036 in the eastern room, and external ditch O.

The timbers survived only as stains of charcoal, lacking detail of the structures they once formed, and were too fragmentary to lift. Likewise, other charcoal was, with a few exceptions, too fragmentary to enable the form of the object to be determined.

2.4.1 Medieval building - construction Structural timbers

Fill 27106 (SS 35) of beam-slot P (intervention 27105) and samples from deposit 27027 (SS 6 to SS 12; SS 14 to SS 30) provide evidence for the materials used in the building's construction (see Data Tables). Charcoal from beam-slot P (SS 35) and burnt timbers 27139 (0.42m long; SS 43), 27140 (3.2m long; SS 44), 27141 (0.6m long; SS 45) and 27138 (0.4m long; SS 42) was identified solely as oak (Quercus) (Figure 8). The oak predominantly consists of large heartwood fragments, with little evidence of curved growth rings, suggesting that trunkwood or large branches were used for the main structural timbers. While the burnt timbers represent collapsed structural elements, the oak charcoal within the beam-slot was most likely washed in after the building's destruction and abandonment. Oak makes excellent structural timber as the tyloses that form within the heartwood vessels cause the wood to become virtually impermeable. The tannins within the wood also act as a fungicide/insecticide, providing further protection (Gale and Cutler 2000, 204–5).

Timber 27058 (1.8m long; SS 31) was identified as willow/poplar (Salix/Populus) roundwood. Anatomical similarities make it impossible to differentiate between these species with certainty. However, willow is a softer, lightweight wood, not typically used structurally, while poplar is a tougher wood, more often utilised in construction (Gale and Cutler 2000, 190 and 237). If this piece was from a beam it is more likely to have been of poplar. A third timber, 27118 (0.65m long, in two pieces; SS 34), was identified as alder (Alnus glutinosa) roundwood. As this was smaller than the other timbers it is unclear whether this was structural, an artefact or just firewood.

Other species possibly representing structural timbers include concentrations of ash charcoal (34%) in Square 8, and beech charcoal in Squares 27 and 28 (21% and 29% respectively), all from deposit 27027. Beech and ash are known for their strength and ash in particular for its resilience when under stress, although both perish easily when exposed to water (Gale and Cutler 2000, 110 and 120). It is possible that this charcoal derived from internal beams, but it is equally plausible that the remains are from furniture or other artefacts. However, three ash dowels were recovered in association with timbers 27141 (Sample 45) and 27139 (Sample 43) and, given the resilience of ash, it is evidently a suitable species from which to make such structurally important items.

Of particular interest was a concentration of hawthorn/rowan/crab apple charcoal in Sample Square 10, making up 71% of the assemblage. No other sample contained such a concentration, suggesting that a specific item was burnt in this area. The location of this grid square, at the entrance to the western room, suggests a wooden door separated the two rooms. The anatomical similarities between hawthorn, rowan and crab-apple wood makes them impossible to differentiate, although construction timbers or planks are known to have been made from these species (Gale and Cutler 2000, 184).

Together, the combined evidence suggests that oak timbers formed the main structure of the building. The willow/poplar branch was substantial and may also have been a beam. Ash and beech may also have been utilised for structural timbers or furniture/fittings. Wattle-and-daub

Wattle-and-daub typically comprises a lattice framework of vertical stakes woven with horizontal twigs/branches, overlain by a mixture of clay, lime, mud, animal dung, horse hair and straw (Morriss 2000). Several pieces of evidence from the plant macrofossil and charcoal remains from the medieval building suggest that it had wattle-and-daub walls.

Figure 11
Figure 11: Composition of charcoal from Sample Squares 6–9, 11-14 combined

The charcoal from deposit 27027 proved difficult to interpret, as concentrations of particular species varied across the different sample squares (see Charcoal Data Table). The charcoal assemblage as a whole is likely to represent structural elements, furniture, and items stored within the building. The analysis of charcoal from samples 6, 7, 8, 9, 10, 11, 12 and 14 (the layer did not spread to 13), located adjacent to the northern and western edges of the building, aimed to identify the materials used in wall construction. Excepting Sample 10 (discussed above), the combined charcoal assemblage for these squares was dominated by willow/poplar (37%) and alder (29%), with oak contributing a further 19% (Figure 11). As suggested above, the oak probably represents remnants of structural timbers, including posts and rails; however, the willow/poplar and alder are more likely to have been the remains of wattle from the walls. These trees were commonly coppiced/pollarded to produce long stems of relatively soft and, in the case of willow, pliable woods (Gale and Cutler 2000, 34, 190 and 236). Alder grows straight and splits readily and would have been suitable for the staves, around which willow (rather than poplar, although the charcoal cannot be differentiated) was woven.

Deposit 27027 included large amounts of vitrified material (probably highly fired clay) with preserved inclusions and impressions of straw and twigs, which seems likely to have been daub (See Charred Plant Remains Data Table). The straw mixture apparently represents a temper, burnt before it had completely decayed. It probably originated from waste produced during the threshing and winnowing of crops, producing coarse straw fragments, rachis and lighter arable weed seeds (Hillman 1981, 134–5) such as corn marigold (Glebionis segetum), corn chamomile (Anthemis arvensis) and black-bindweed (Fallopia convolvulus), all of which are present within the plant macrofossil assemblage from this deposit. In addition, a number of medick (Medicago), clover (Trifolium), buttercup (Ranunculus) and cinquefoil (Potentilla) seeds were identified. These are typically pasture species, perhaps included within animal dung.

Consideration has been given to the possibility that the weed seeds from deposit 27027 represent the remnants of burnt thatch. Letts (2001, 12) indicates that medieval thatch comprised a base-coat of threshing waste (straw, chaff along with weed seeds), followed by an external 'spar' coat of higher quality straw, of which bread wheat was one of the principal components. Given the good survival of a relatively large number of light and fragile weed seeds, thatch might reasonably be expected to be signalled by more surviving straw remains, which are not present here in significant amounts. Furthermore, Letts (2001, 13) has suggested (contrary to popular belief) that thatched roofs were typically too damp to burn easily, and it appears likely that the burnt plant remains come largely from material in the building, with perhaps a small component falling from the roof. A number of sedge (Carex), amphibious bistort (Persicaria amphiba), water-pepper (Persicaria hydropiper) and spike-rush (Eleocharis) seeds, grass stems/seeds and straw were also identified. Rushes, sedges and reeds may have been used as components of thatch and their inclusion may indicate that marshland species formed at least some of the thatch here; however, the absence of stems makes this suggestion difficult to verify. Alternatively, these species may relate to the use of reed matting in the building, although there are no spatial concentrations directly indicative of this. Given the location of the site close to the Otter floodplain, however, this resource may well have been to hand and exploited.

2.4.2 Medieval building – use Main Room (see Data Tables)

Rectangular oven 27101 (SS 33) was located in the north-east corner of the structure. Its primary fill, 27102, contained a single vetch/pea seed along with charcoal, identified as beech, alder/hazel, ash, oak and hawthorn/rowan/crab apple, representing in situ firing debris. Pit 27122 (SS 41) contained a single oat grain and a moderate amount of charcoal identified as alder/hazel, maple, elder, oak, hawthorn/rowan/crab apple and cherries, probably representing firing debris from oven 27101. The charcoal from both features was recovered in relatively low quantities, but suggests that fuel came from a variety of wood sources.

Most of the evidence relating to the building's use derives from the remains found in burnt deposit 27027, which provide a snapshot of the contents of the building at the time of the fire. Although this deposit spread across most of the floor of the central and western rooms, the main discoveries of interest came from the western room (below). While some remains were found in the grid squares in the main room (Squares 6–9, 18–21 and 22–26), these are low in number and lack any distinctive composition, suggesting a heterogeneous origin. This includes material over and around the hearths (Figure 4; 27091 and 27095). Western Room (see Charred Plant remains Data Table)

Crops identified from deposit 27027 in the western room include oats (Avena), free-threshing wheat (Triticum aestivum/Triticum turgidum/Triticum durum), rye (Secale cereale), barley (Hordeum vulgare), garden peas (Pisum), broad beans (Vicia faba) and vetches/peas (Vicia/Lathyrus). In addition, a small number of wheat rachis confirms the cultivation of both bread wheat (hexaploid) (Triticum aestivum) and club wheat (tetraploid) (Triticum durum). It does not seem likely that the quantity and concentration of crops here derived from a thatched roof. Grain, beans and peas were distributed across all grid squares and there were concentrations of particular species in specific areas, suggesting that this room had been used for crop storage. The crops from Sample Squares 27 and 28 are broadly supported by the smaller quantities from the evaluation trench here.

Figure 12
Figure 12: Composition of plant remains from floor of medieval building [Download full size image]

Analysis by sample square suggests that oats, broad beans and peas were stored in the area of Square 16, vetches/peas in Square 30, and rye and free-threshing wheat in the area of Square 29. There are also a moderate number of oat grains identified in Square 11 and Square 15, although, given the abundance of oat within Square/Sample 16, it seems likely that these represent 'overspill'.

There is no evidence to indicate whether the individual crops were stored in separate containers. It was common during the medieval period for crops to be grown as mixed cereals/legumes to buffer against crop failure (Moffett 2006, 50) and, given the composition of the assemblages in this room, it is possible that mixed crops were stored together. For example, the grouping of oat, peas and broad beans in Sample 16 may indicate the presence of a crop mixture known as bulmong or harascum, used mainly for fodder, for soil improvement (by fixing nitrogen) and for pottage. The grouping of free-threshing wheat and rye in Sample 29 may point towards maslin (wheat-rye mix) or 'mancorn', used for making bread (Stone 2006, 13).

Oats, wheat, barley and rye were standard cultivated crops in the medieval period in Devon. The dominance of oats is comparable with other sites in the county such as Exwell Barton (Cobain 2014, 164) and Sourton Down, Okehampton (Straker 1997, 115) and provides support for Rippon's (2012, 258) statement that oats was the most prevalent crop west of the Blackdown Hills.

Archaeological evidence for legumes is often limited as they do not require exposure to heat for processing. Combined with documentary evidence cited by Fox (1991, 305–6), Rippon (2012, 260) concludes that legume cultivation was less prevalent to the west of the Blackdown Hills than further east; however, evidence from this site suggests that they were being cultivated in East Devon during the medieval period.

The unidentifiable mixture of vetches (some apparently stored within their pods) in Square 30, in the southern part of the western room, is of interest. These were all too small to be garden pea/broad bean, but may include common vetch (a known cultivar) or other wild vetches. Vetches were principally used for fodder, only being used for human consumption during years of very poor harvest (Moffett 2006, 53).

Analysis of the charcoal sought to identify potential containers used to store the crops, by examining grid squares with high concentrations of plant remains (Squares 11, 16, 29 and 30; Figure 10). Square 30 was dominated by willow/poplar charcoal (95%), with a high proportion of fragments having curved growth rings, indicating the presence of twigs or narrow stems. This dominance may suggest that the vetches were stored in a willow basket. Square 16 was dominated by oak. This may have been from a structural timber and so, in order to understand how other species were represented, 100 non-oak fragments were identified. Of these, 87% were willow/poplar; as with Square 30, the dominance of willow/poplar is suggestive of a willow basket.

Square 11 and Square 29 (Figure 10) were represented by willow/poplar (38% and 30% respectively) and alder (26% and 28%). Square 11 was adjacent to the wall of the building and, given the similarity of this assemblage to others along the wall, the charcoal may represent burnt wattle rather than crop storage containers. Square 29 was more central, but as it has similar proportions of alder and willow/poplar to many other squares it is impossible to suggest the presence of a container. If lighter woven storage containers such as sacks were used, as might be expected for grain such as wheat and oats, all evidence may have been destroyed during the fire. Other features

Posthole 27151 (SS 47), which marked the entrance to the western room, contained a moderate amount of charcoal identified as alder/hazel, hazel and oak (it contained no plant macrofossils). The origin of this material is unclear, although the mixed assemblage does not suggest that the post was burnt in situ.

Oven 27137 (SS 46) contained a single free-threshing wheat grain and charcoal of oak, alder/hazel, hazel and ash (Figure 4). Nearby, occupation deposits 27072 (SS 36) and 27084 (SS 37, SS 38 and SS 39) are interpreted as being contemporary with the building's use (before the conflagration). Abundant charcoal comprised alder, alder/hazel, birch, oak, ash, hawthorn/rowan/crab apple, cherry species and willow/poplar. Small amounts of charred material included oats, barley, rye and free-threshing wheat grains, cereal chaff including culm nodes, and straw and wild radish (Raphanus raphanistrum) perianiths. This material probably originated from rakings from oven 27137. The limited charred plant remains from the oven and occupational deposits 27072 and 27084 make it unlikely that the oven was used for crop processing, and the relatively high number of culm nodes/straw probably represents floor sweepings burnt in the fires. A similar interpretation can be advanced for the remains in oven 27101 in the corner of the main room. It is possible that additional fires were lit to keep the building dry to avert crop spoilage; the catastrophic fire may have originated in one or other oven. The charcoal assemblage from this set of deposits differs from the charcoal deposits associated with the fire event, with slightly higher percentages of 'other species' such as hazel (13%), birch (8%) and cherry (6%) more characteristic of fuel used in small domestic fires. External features (see Data Tables)

Fill 27047, within ditch O (slot 27047) (SS 32), contained a small number of oat and rye grains, a wild radish perianith, a small amount of vitrified material and two alder/hazel charcoal fragments. This deposit is interpreted as levelling after the building went out of use; the small amount of charred and vitrified material is likely to have come from burnt debris from the conflagration.

Pit 27036 (SS 5), in the eastern room (Figure 4), contained a large assemblage of plants including oats, barley, free-threshing wheat and rye cereal grains, cereal chaff including barley, rye and bread wheat rachis, cultivated and wild oat paleas, culm nodes, straw, broad bean and vetch seeds and a selection of arable (corn marigold, wild radish, corncockle, hemp-nettle (Galeopsis)), opportunistic (bramble (Rubus), cleavers (Galium aparine)), grassland (grass species, ribwort plantain (Plantago lanceolata)) and marshland (sedge, water-pepper) seeds. Charcoal was abundant with oak dominant and some alder/hazel and willow/poplar. As above, while it is possible that this assemblage represents collapsed and burnt thatch, it is typical of crop-processing waste and may be a mixture of crop waste retained for future use (fodder, temper or fuel), subsequently burnt as fuel.

2.4.3 Reconstruction of the local landscape and woodlands

The charcoal evidence indicates the use of oak, alder and willow in the building's construction, with possible willow baskets/containers used inside. Fuel wood in ovens/hearths was recorded as alder, hazel, birch, oak, ash, hawthorn/rowan/crab apple, cherry and willow/poplar.

Increasingly depleted woodland during the medieval period meant that ownership and rights were far more complicated than they are today (Rackham 2001, 62). Oak would have been a sought-after timber, probably brought to the site from outside. The remaining wood, used for much of the wattle-and-daub construction and probable willow baskets/containers, was more likely locally sourced. The site is located 150m west of the River Otter, and alder-carr woodland would have flourished on the river's floodplain, where the coppicing of alder and willow would allow long, straight stems to be produced. Hazel, birch, hawthorn/rowan/crab apple and cherry all prefer drier conditions, and these woods were probably gathered from hedgerows or small stands of trees on drier land further west. Drier land surrounding the site was likely used for growing oats, barley, rye and free-threshing wheat crops, stored and threshed in a barn.


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