Reconstruction of historical forest cover on a 1° grid in central and southeast Europe from AD 1800 to 2000

The natural vegetation has been substantially changed over the last millenium, especially from forest to agricultural areas in Europe. To study the effects of deforestation on carbon and climate system, it is essential to construct spatially precise maps in forest cover. The current representative historical forest data sets are either derivatives of agricultural datasets or are produced based on the deforestation-population relationship. Almost no attempts have been made to use the inherently linked relationship between deforestation and cropland expansion that has run through Europe for millennia. This study created an approach based on the relationship between cultivation intensity and forest fraction to reconstruct forest cover changes in central and southeast Europe from AD 1800 to 2000 by the following steps: (1) To develop the spatial relationship curve (spatial resolution is 1°) between the “cultivation intensity (0–100%)” and the “forest fraction (0–100%)” derived from modern land cover datasets; (2) To generate the national-scale cropland data based on historical records from AD 1800 to 2000, and to allocate them to a 1° pixel; (3) To reconstruct the forest cover using the aforementioned relationship curve and the historical gridded cropland database. The results show that: (1) The forest fraction in central and southeast Europe decreased from 38.4% in AD 1800 to 27.0% in AD 1900, and then increased to 32.5% in AD 2000. (2) In AD 1800, large areas of forests can be primarily found in Luxembourg, Netherlands and Belgium, the south of France, the south of Germany, the Alps region, Poland, and the majority of the Balkans. (3) Throughout the 19th century, the entire region was generally subjected to deforestation, with large areas of forest coverage only being preserved in the Alps and the western and southern Balkans after 100 years of exploration. (4) The forest coverage in most of the study regions increased again at the end of the 20th century.