- People and Nature in the Celtic World -
and hedged pasture with some cultivated land and beyond that rough grazing.
Woodland that remained was secondary and probably managed (Smith 1979). In the
Severn and Avon valleys of the Midlands there is evidence of greatly increased soil
erosion in the first millennium BC at a time of increased clearance (Shotton 1978;
Brown 1987).
British Highland ZoneThis area of old hard rocks, with mostly poor soils and high rainfall in the west and
north of the British Isles was, in general, cleared significantly later than the Lowland
Zone, much of it in the mid-to late Iron Age. Earlier prehistoric clearances were
mostly small, localized and temporary. In north-east England these gave way between
C.IOO BC and AD 200 to much more widespread clearances (Turner 1979). As Figure
9.2 indicates, on some sites clearance certainly began before the Roman conquest
and is of native iron age origin. It also occurs at a range of altitudes and topographic
locations, encouraging the impression that it was widespread. Roman military sites in
the Central Lowlands of Scotland were also constructed in an essentially pastoral
heath landscape which can sometimes be shown to have formed as a result of grazing
pressure in the preceding couple of centuries (Robinson 1983; Boyd 1985). Other
sites, especially along Hadrian's Wall, show increased clearance during the Roman
period but elsewhere woodland survived later. Major deforestation in parts of the
Lake District occurred around AD 400 and in south-west Scotland later in the first
millennium AD (Turner 198 I; Dickson et al. 1978). On the exposed coastal areas in the
north and west of Scotland and the islands, heathland, moorland and blanket bog
communities had developed well before the first millennium Be. By then virtually no
woodland remained and the environmental evidence from broch settlements reflects
an open landscape with much pastoral and arable activity (Mackie 1974; Dickson and
Dickson 1984).
In Wales, many upland areas had developed moorland and blanket bog plant
communities before the Iron Age. Environmental evidence from the Breiddin
hill-fort (Musson 1991) reveals several episodes of human impact before the final
removal of trees in the first millennium Be. In the more remote parts of Wales,
however, as in northern England, many areas remained wooded. The environs of
Tregaron Bog were cleared around 400 BC as a result of pastoral activity during the
period of hill-fort building. Once established, the largely pastoral environment
continued until the Medieval period (Turner 1964). Despite the pollen evidence for a
largely pastoral landscape, plant remains from iron age enclosures in both Wales
(Caseldine 1990) and northern England (van der Veen 1992) show that crop growing
was widespread, although limited in scale, indicating that the old model (Piggott
1958) of an almost entirely pastoral Highland Zone can no longer be sustained.
Ireland
By the first millennium BC moorland was extensive on the high-rainfall west coast
and peats were increasingly blanketing the landscape, covering, for instance, former
bronze age fields on Valencia Island (Mitchell 1989). Several areas which had beenIp