THE VEGETATIONAL HISTORY OF PARTS OF SOUTH AND EAST DURHAM

Abstract

SUMMARYLate‐Devensian and Flandrian deposits are described from six sites in lowland Durham, ranging from Neasham, near Darlington, in the south, to Thorpe Bulmer, near Hartlepool in the north‐east. Pollen diagrams from each site are presented and show the changes in vegetation of the different areas. At Thorpe Bulmer the tundra vegetation of the Older Dryas period gave way to rather open birchwoods in the Allerod and there was then a return to sedge tundra in the Younger Dryas. This sequence is compared with others in Durham, Yorkshire and Northumberland. The Flandrian sequence opens with the development of birchwoods followed by the appearance of the more thermophilous forest trees. There are in the late Boreal and early Atlantic periods local differences in the forest, as for instance in the early establishment of alder at Mordon Carr (7760 B.P.) and the prevalence of pine around Bishop Middleham, the latter being related to the close proximity of Magnesian Limestone. The ‘elm decline’is dated at 5500–5200 B.P. and there are after that a number of clearance phases beginning with small scale clearance by Neolithic people from about 5200 B.P. From the Bronze Age on there are local differences, again presumed to be related to the proximity of Magnesian Limestone and to soil differences. At Bishop Middleham there is a massive clearance of forest and spread of pasturing from 3660 B.P., reaching a maximum at 3360 B.P. (Middle Bronze Age) when cereal cultivation was introduced. Except for Hutton Henry where there was considerable clearance the rest of the area saw only moderate and temporary clearance at this time. At Thorpe Bulmer there is evidence for intensive cultivation of hemp and some cereals from 2064 B.P. (Late Pre‐Roman Iron Age) rising to a maximum in the Roman period (1730 B.P.) and continuing at a low level until the Norman Conquest (852 B.P.). At nearby Hutton Henry there is evidence for extensive agriculture around 1842 B.P. but in the southern part of the region such clearance was not reached until much later (1213 B.P. at Neasham). In all these deposits there are interesting differences in rate of peat growth from one period to another and at Thorpe Bulmer there is a very long break in the sequence.