As the number of sites with palaeoenvironmental evidence grows, it becomes increasingly 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 increasing proximity of Roman markets.
It is often suggested that the collapse of the Roman Empire led to large-scale woodland regeneration. There is late and post-Roman expansion of beech in regenerated woodland in many parts of Europe (Behre 1988). In Brittany a reduction in agriculture occurs in the third century, apparently as a result of Roman-inspired population movements (Marguerie 1990). In the British Isles some sites show post-Roman regeneration, but sometimes centuries after the collapse of Rome (Turner 1979). Generally, however, the extent of regeneration has been exaggerated, partly because, where dating evidence is poor, there is a temptation to make simplistic correlations between vegetation changes and the inferred cultural sequence in an area. There is a surprising number of sites with pollen evidence of continuity of agricultural activity, indeed sometimes continuity in the growing of specific crops, from Roman to postRoman times (Bell 1989).
World History
