The distribution of the tree of heaven (Ailanthus altissima (Mill.) Swingle) in the settlements and forests of Southern Börzsöny, Hungary

Abstract

: In this study, we investigated the occurrence of the invasive alien tree of heaven (Ailanthus altissima) in the approximately 2,100-hectare area of Southern Börzsöny, along the road network in settlements Zebegény and Nagymaros and in forests. Th e survey was carried out according to the abundance and location of the species (for all occurrences), the maintained or neglected status of the area (for settlements), and the open or closed nature of the stand (for forests). Individuals or more coherent stands of the tree of heaven were recorded using handheld GPS. A new point was taken when the distance between two individuals or stands exceeded 10 m. We recorded 482 occurrences of tree of heaven in the two settlements and found that it occurs most frequently in neglected public green areas (38%) and neglected gardens (21%), and oft en shows up along railway lines (18%). In forested areas between the two settlements, we recorded 193 occurrences and found that the tree occurs mainly along regularly used forest roads (42%), and most frequently in open stands (especially in artifi cial gaps) (69%). Our study also points out that the Hungarian National Forest Inventory data indicate signifi cantly fewer occurrences (covering 23 subcompartments) than our forest mapping survey or earlier ones by other researchers (56 and 60 subcompartments, respectively). Based on our results, anthropogenic impacts are crucial for the spread of the species. Th e tree is expected to spread exponentially in the future, so in order to prevent this, we recommend that treatments are carried out as soon as possible, with the immediate eradication of seed-producing individuals. Th e issue of social perception and knowledge is also crucial, as the majority of the society generally has little knowledge of both the tree of heaven and the dangers posed by invasive plant species. Targeted education of the public can therefore be an important element of prevention.