Control treatments for tree of heaven (Ailanthus altissima (Mill.) Swingle) and silvicultural guidelines for potentially invasive alien tree species within managed forests of Slovenia.
The tree of heaven is one of the most widespread non-native tree species in Slovenia. In most areas, its spread occurs in non-forested areas, yet recent observations indicate it is becoming more common within some forest ecosystems as well. Since chemical treatment is banned in Slovenia, this study tested the effectiveness of three mechanical control treatments. Breakage of annual and biennial shoots was not successful; the best treatment was total removal by pulling seedlings and saplings. Mechanical control of invasive tree species is more effective if combined with other management approaches, such as practicing silviculture that promotes vertically diverse stands of native tree and shrub species, particularly small-scale silviculture that maintains a subcanopy layer.