Long-term land-cover changes in the Belgian Ardennes (1775-1929): model-based reconstruction vs. historical maps

Understanding long-term human-environment interactions requires historical reconstruction of past land-cover changes. The objective of this study is to reconstruct past land-use and land-cover changes in a rural municipality of the Belgian Ardennes over the last 250 years. Two approaches were compared. The first approach produced backward projections based on a mechanistic model which computes the demand for different land uses under the assumption of an equilibrium between the production and consumption of resources. The second approach involved using a series of historical maps to extract directly land-use areas. A stochastic Markov chain model was also used to project backward missing land-cover data in the time series. The consistency between the results obtained with the different approaches suggests that land-use area can be successfully reconstructed on the basis of the mechanistic model, under conditions of a subsistence farming system and a closed economy. Land-use/cover changes in the Belgian Ardennes from 1775 to 1929 were more driven by the interventionist measures of the Belgian government and by technological progress than by the 'pressure' of the growing population and livestock. Thanks to agricultural intensification, a decrease in land under human use was supporting increasing human and livestock populations from 1846 to 1880. Reforestation has accelerated since the mid-19th century. This case study illustrates the highly dynamic and non-linear character of land-use change trajectories over long time periods and their strong interactions with the history of societies.