The distribution of Tree-of-Heaven (Ailanthus altissima (Mill.) Swingle, Simaroubaceae) in the Area of “Đerdap National Park”

Abstract

Tree-of-Heaven is an invasive tree species that disturbs the biodiversity and is particularly important in protected areas. On the basis of its investigated spatial distribution in the “Đerdap National Park”, Tree-of-Heaven is most represented on the edges of the National park, close to Danube, where the anthropogenic influence is most pronounced. Having in mind that the roads and watercourses are the main corridors for expansion of invasive tree species and that the full lenght of the borders of “Đerdap National Park” are matching these corridors, it can be assumed that Tree-of-Heaven was present in the area since the XIX century as the species was used for reforestation of Ramsko-Golubačka and Deliblato Sands that are in the upstream part of the Danube close to the “Đerdap National Park” borders. Due to the construction of the state road (“Đerdapska magistrala”) along the borders of the National park, Tree-of-Heaven gradually colonized the rocky road cuts going from lower towards higher attitudes. It can be expected that Tree-of-Heaven will be permanently present in the area in the upcoming period as the terrain of the rocky road cuts is unapproachable and recently colonized by Tree-of-Heaven. Significant individual or group distribution of Tree-of-Heaven in the area of “Đerdap National Park” is recorded close to and in the area of the protection regime I, on localities of great scientific importance such as “Kanjon Bolјetnske reke” and “Lepenski vir”. Individual trees that have 55.0 cm diameter at breast height and height of 25.5 m, point out to their presence in the area for decades. For now, the expressed dendrodiversity and the fully closed canopies of the surrounding forest stands are disenabling the expansion of this invasive species to the area of forested hilly and mountainous hinterland of the National park.