Late Quaternary vegetation history of the acidic lithologies of South East England

• Main Author: Groves, Jonathon Alexander
• Published: Kingston University 2008
• Subjects: 560.179; Geography and environmental studies
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497594

There have been few Late Quaternary vegetation records from the acidic lithologies of south east England. This study reports on investigations from three new valley mire sites (Bagshot, Conford and Hurston Warren), using pollen and charcoal analyses with chronologies provided by radiocarbon dating. The Bagshot sequence begins at c. 12750 cal. BP with high Betula and Pinus sylvestris pollen values recorded during the late-glacial and early Holocene respectively. After a hiatus from c. 9800 to c. 7550 cal. BP, the dominant taxa are Quercus, Tilia and Corylus avel/ana-type. Tree pollen values decline from c. 3750 cal. BP, with Calluna vulgaris recorded from c. 3450 cal. BP. At Conford, high Pinus sylvestris values persist for c. 4700 cal. years from c. 10750 cal. BP. Increases in Quercus, Tilia and Alnus glutinosa occur at c. 6050 cal. BP. Here, tree pollen values decline from c. 2900 cal. BP with Calluna vulgaris then consistently recorded, along with other indicators of anthropogenic activity. The Hurston Warren sequence begins at c. 4400 cal. BP with high Quercus, Tilia and Corylus avellana-type pollen values. A fall in Tilia percentages from c. 3050 cal. BP is again followed by higher Cal/una vulgaris values and the appearance of anthropogenic indicators. Discussion focuses on the vegetation history of Pinus sylvestris in lowland England, anthropogenic activity associated with declines in Tilia pollen values and the development and persistence of heathland. In the early Holocene, while Pinus sylvestris was rapidly excluded from the more fertile soils of lowland England, in areas of poor sandy soils Pinus sylvestris often achieved dominance, which locally persisted into the mid-Holocene. Examination of palaeoecological trends associated with declines in Tilia abundance across lowland England has led to the identification of a number of processes that are responsible, though the majority of the declines are associated with clearance activity. The latter primarily occur during the Late Neolithic to Mid-Bronze Age. Their number is substantially reduced from the Late Bronze Age; however, this may in part reflect the scarcity of remaining Tilia woodland. The earliest of these declines appear to have occurred in areas of fertile soil; though by the Mid-Bronze Age they are focussed on the acidic geologies of south east of England. Extensive heathland development did not occur in these areas until the Bronze Age when expansion is associated with either an increase in pastoral activity or the frequency of burning. Once established, heathland areas appear to have been maintained into the historic period by these traditional management practices. At Hurston Warren and Conford, heathland areas appear to have expanded during the Anglo-Saxon and early Medieval period respectively.