Mapping the Legacies of Historic Charcoal Production
Abstract:The historic production of charcoal is an important component of the late Holocene fire history for many landscapes. Charcoal production can have numerous effects on ecosystems, e.g., through changes in forest area and structure, or through the effects of pyrolysis, charcoal and ash addition to soils. To assess such effects, it is necessary to understand the spatial extent and patterns of historic charcoal production, which has so far hardly been approached for the Northern European Lowlands.
In the forefield of the open-cast mine Jänschwalde (north of Cottbus, Germany), archaeological excavations have revealed one of the largest charcoal production fields described so far. For this area, we applied and evaluated different methods for mapping the spatial distribution of charcoal kiln remains. We present methods and results of our work in this exceptionally well-described charcoal production field and of additional studies on kiln site distribution in regions of the Northern European Lowlands. The large-scale excavations in the mine forefield provide exact information on kiln site geometry. Using airborne laser scanning elevation models, the mapping of kiln sites could be extended to areas beyond the mine forefield. To detect kiln sites for larger areas, an automated GIS based mapping routine, based on a combination of morphometric parameters, was developed and evaluated.
By manual digitization from Shaded Relief Maps, more than 5000 kiln sites in an area of 32 km2 were detected in the Jänschwalde mine forefield, with 1355 kiln sites that are wider than 12 m. These relatively large kiln sites could be mapped with detection rates that are close to those of manual digitization using the automated routine. First results for different study areas indicate that charcoal production is a so far underestimated component of the land use history in many parts of the Northern European Lowlands.