Peat from a bog near Edinburgh contains 11,500-year-old vegetation and glimpses of the impact made by humans on the landscape from as far back as the Neolithic period.
     Ravelrig bog contains two hill forts. Kaimes Hill shows evidence of human activity from the Mesolithic period. Dalmahoy Hill is thought to have been occupied during the pre-Roman Iron Age and early medieval times.
     "The bog started out as a small lochan [lake] within a rocky hollow that was formed at the end of the last glacial period," says archaeo-botanist Susan Ramsay. "Aquatic plants gave way to marshland and finally raised Sphagnum [peat] bog as natural succession progressed. During the early Holocene, the woodlands of the area were dominated by birch, hazel and willow but developed into mixed oak, elm and hazel woodlands by the mid-Holocene."
     An initial survey in 2007 revealed the scientific potential of a core deposit covering more than 10,000 years.
     "Previous studies have suggested that the first major woodland clearances in central Scotland occurred in the pre-Roman Iron Age, with the cleared agricultural landscape being maintained throughout the Roman period," says Ramsay. At Ravelrig, human impact on the landscape is recorded from the Neolithic period onwards, with increasing woodland clearance and agricultural activity in the Bronze Age and a peak in activity in the pre-Roman Iron Age. These periods of agricultural intensification appear to correspond with known periods of occupation at the nearby hill forts."
     Ramsay says that between 250 BCE and 150 CE, "Birch pollen levels increased significantly, suggesting that land that was previously farmed was abandoned and was gradually colonised by birch woodland. It is not clear what the cause of this agricultural decline might be but further work may be able to determine a more precise date range for this event," believes Ramsay.

Edited from Culture24 (21 October 2014)