Towards a more accurate quantification of human - environment interactions in the past pages:45-46
Open PAGES Focus 4 Workshop Human-Climate-Ecosystem Interaction location:University of Leuven date:3-7 February 2014
Reconstructing rates and patterns of erosion processes in the distant past is often complicated by the fact that subsequent erosion in later periods destroys former erosion features. For instance, permanent gullies which form during intense rainfall events on agricultural land are being infilled by the gradual delivery of sediment during less intense rainfall events. Similarly, 46
traces of human impact in the landscape become obliterated due to continuous cultivation practices (tillage erosion and deposition). This is especially the case for the loess belt in NW Europe, including those in central Belgium, which have been cultivated very intensively since the Roman and Medieval Periods. However, some traces of ancient erosion phases and human activities are still preserved under old forests. The Meerdaal Forest in central Belgium offers a unique setting to study such gully erosion phases and other traces of human impact, such as closed depressions testifying ancient quarrying for calcareous loess, as it has been under forest at least since the 12th century. The spatial pattern of gully systems and closed depressions can be related to the spatial patterns of human occupation and ancient road networks. Radiocarbon and OSL dating of gully fan deposits, artefacts and the infill of closed depressions point out that some of these features were formed in the Bronze Age, Iron Age and Roman Period. Contemporary gully erosion studies allow one to better understand the land use and rainfall conditions that lead to the development of these gullies. This suggests that parts of the landscape that are nowadays covered by old forests must have been used more intensively in previous periods. More geomorphic research in old forests is needed to better understand human-environment interactions in prehistoric and historic times.