Legacies of past human activities on one of the largest old-growth forests in the south-east European mountains

International audienceThe Dinaric Mountains are a region considered as a hotspot for remaining late-successional montane mixed Abies alba-Fagus sylvatica-Picea abies old-growth forests presumably because historical deforestation levels were substantially lower than in other European regions. We present new well-dated stand-scale palaeoecological records (pollen, spores, stomata, macrofossils, macroscopic charcoal, and magnetic susceptibility), an extensive dataset of current forest structures and a detailed land-cover types map from the Biogradska Gora forest to provide new insights into the long-term vegetation dynamics of old-growth forests in the montane zone of the Dinaric Mountains. Land use (cereal crop cultivation, cattle herding, and fire) during the Middle Ages caused a reduction of the A. alba and P. abies-dominated forest. After a major land-abandonment event around the Black Death pandemic (mid-14 th century) and more moderate land-use phases associated with fire episodes, which favoured the short-term expansion of light-demanding pioneer species (Corylus and Betula), F. sylvatica-dominated stands developed in the more accessible outer part of the forest. The legacy of past land uses is still visible as the structure of the almost pure F. sylvatica stands shows less old-growth characteristics. Most strikingly and markedly in contrast to decreasing tree cover due to generally intensifying land use elsewhere in Europe, tree cover increased several centuries before the formal protection of the forest (1878 CE), supporting the view that historical land-use pressures played an important role for the small extent and the continuity of disturbance-sensitive A. alba and P. abies-dominated old-growth stands