STUDIES OF THE POST‐GLACIAL HISTORY OF BRITISH VEGETATION

Abstract

S ummary Two boreholes in the organic deposits of Old Buckenham Mere, Norfolk show that accumulation began in the Late‐Glacial period. The rich pollen flora from two boreholes shows great similarities with that of three other Late‐Glacial sites in the region, and differs from that of the Late‐Weichselian at Colney Heath mainly in the prevalence of tree birches. Above a depositional hiatus shown to correspond with most of pollen Zones V, VI and Vila, borehole 2 has 7 m of uniform organic muds to which a conjectural timescale has been applied. Thus the detailed pollen diagrams can be correlated with pre‐historic and historic events from early Neolithic to the present day. For this period the diagrams yield evidence of the changing kind and intensity of forest exploitation and destruction, and particularly the great extension of arable cultivation in Anglo‐Saxon times. The re‐expansion of many Late‐Glacial plants as weeds and ruderals is evident and analysis of the changing frequencies of trees and shrubs accords with explanations in terms of anthropogenic rather than climatic effects. There is now remarkable continuity of evidence of the character of East Anglican vegetation from Full‐Weichselian time to the present day.