Vegetation and Land-Use History at Diss, Norfolk, U.K.

Abstract

(1) A pollen diagram from Diss Mere provides a detailed vegetation history for central East Anglia. In the early stages of sediment deposition in the mere (Devensian late-glacial), Betula woodland covered the landscape. Intially the woodland was open, containing a variety of herbaceous taxa, but later a more closed canopy developed. (2) Betula was replaced primarily by Corylus, which spread rapidly into East Anglia early in the Holocene. Pinus was then probably absent locally, in contrast to sites nearby. (3) The Corylus woodlands gave way to mixed-deciduous forests containing Tilia, Ulmus, Quercus, Corylus and Fraxinus, with Alnus in moist areas. (4) Possible anthropogenic influence on the vegetation is first recorded soon after the development of these mixed deciduous forests. Neolithic people may have made clearings, but these were apparently soon abandoned and recolonized by Corylus. Ulmus populations were permanently affected by these early disturbances, never fully recovering their former abundance. Coincident with these first disturbances was the expansion of Taxus, which became locally abundant, perhaps expanding in woodland openings. (5) Forest clearance, including the selective cutting of Tilia and the cultivation of Hordeum and other cereals, indicates the local presence of prehistoric (Bronze Age) settlements in the catchment. (6) The most marked cultural effect on catchment vegetation was the complete clearance of the forest and the conversion of cleared land to agricultural use in the Iron Age. The Diss Mere sediments record in detail the subsequent changes in land-use, agricultural practices and the development of the town. Iron Age pastoral farming was followed by the introduction of various crops from Anglo-Saxon times onwards, of which Secale, Cannabis and Linum were of particular importance.