Woodland clearance in west-central Scotland during the past 3000 years

Abstract

Pollen diagrams were produced from peat profiles taken from four raised bogs in west- central Scotland: Walls Hill Bog, Lochend Loch Bog, Lenzie Moss and Gartlea Bog. These sites have produced a detailed overview of the vegetation changes brought about by human impact in the area over the last three thousand years. This picture has been enhanced by peat stratigraphy diagrams, charcoal estimations and suites of accelerator radiocarbon dates from three of the four sites. Pollen influx data was also collected but not used in the final interpretations as it added little of value to the results from the relative pollen diagrams. The evidence is for low levels of woodland clearance in the Bronze Age followed by an increase to extensive clearance in the late pre-Roman Iron Age at Walls Hill Bog and Lochend Loch Bog. Lenzie Moss and Gartlea Bog show clearance to be slightly later, around the time of the Roman invasion and occupation. Clearance is maintained throughout the Roman period and for several centuries after the Roman withdrawal at all the sites, except for Walls Hill Bog. All the clearance activity seems to have been to produce pastoral rather than arable agricultural land. Throughout the Dark Ages agriculture declined and there was extensive woodland regeneration, first of Betula and then the other major tree taxa. Extensive clearance is next apparent between 800 - 1000 cal AD (perhaps slightly earlier at Gartlea Bog) with the cleared land again used for grazing. There is then a short period of woodland regeneration at all but one of the sites before the more extensive clearances of the Medieval and post-Medieval period are seen. These are again characterised by pastoral indicators although cereal cultivation may have become more important during this period. Evidence for modern tree planting is evident at some of the sites and all but Gartlea Bog show some truncation of the top of the peat profile