- People and Nature in the Celtic World -
partly cleared and cultivated in the Bronze Age were subject either to regeneration
or moorland development in the Iron Age, indicating reduced agricultural activity
(Mitchell 1986; Lynch 1981), which is in contrast to most of the other areas discussed.
There are, however, individual sites which show marked clearance in the first
millennium BC (Turner 1981). The Corlea trackway, dendrochronologically dated
148 BC, ran across a very large bog, the surroundings of which were still essentially
wooded, although there was clearance at the time of trackway construction (Raftery
1990). Significantly, a number of sites recently dated by dendrochronology show
that this period was one of major social change and monument construction, yet
the contemporary environmental impact seems to have been more limited than in
northern Britain and many other parts of western Europe.
In Ireland the really significant change takes place after about AD 300 in the Early
Christian period, when there is much evidence for permanent clearance and arable
activity throughout Ireland. This is confirmed by dating and environmental evidence
from raths and crannogs and by a series of dendrochronologically dated horizontal
grain mills (Mitchell 1986; Baillie 1982), which are of seventh-to tenth-century date
and indicate a high level of arable activity. In the case of Ireland, the environmental
evidence seems to support the traditional picture of the flowering of Celtic culture
and agriculture in the wake of the Roman Empire's collapse.
CONTINUITY AND CHANGE
As the number of sites with palaeoenvironmental evidence grows, it becomes increas-
ingly possible to evaluate the extent to which environmental changes are coincident
with, or independent of, the major periods of change attested in historical sources,
settlement patterns or artefact assemblages. In addressing this issue we need to
consider to what extent current dating is sufficiently accurate to distinguish, for
instance, iron age and early Roman clearances. In this regard the growing number of
dendrochronological dates (Baillie 1982) will, in future, assume particular significance.
On present evidence there are few sites which show dramatic environmental
change at the beginning of the Iron Age. Many, however, show marked, sometimes
permanent, clearance in the two centuries preceding the Roman conquest. In northern
Britain, at least, the dating evidence seems solid enough to support this inference
(Turner 1979). There may be a connection between these changes and the increasing
social complexity and nucleation of the later Iron Age. It is, however, a pronounced
phenomenon well to the north and west of the area where, for instance, oppida occur.
In some areas the late iron age environmental changes seem to be more dramatic
than those consequent upon the Roman conquest. In the Manching area of Bavaria
botanical evidence indicates continuity across this key interface and the Mediterranean
plants which the Romans introduced were largely confined to the towns (Kuster 1991).
During the Roman period clearances in many areas were extended and land-use
intensified but the interesting thing about this phenomenon is that it is also present
north of the Limes (Behre 1988). It could therefore be argued that it is a continuation
of the native-inspired changes of the later Iron Age, albeit encouraged by the increas-
ing proximity of Roman markets.