Volatile compounds from leaf litter of invasive alien Ageratina adenophora are known to inhibit growth of native species in sub-tropical Asia, but there is not much evidence if the litter affects tree species. In particular, the relative importance of airborne inhibition versus belowground effect of invaded soil on tree species is rarely explored. We used A. adenophora uninvaded and invaded soils to follow germination and seedling growth of a native Nepalese tree Schima wallichii (DC.) Korth. in the presence and absence of leaf litter of A. adenophora. We also compared diversity of native species in the uninvaded and invaded sites in Nepal. We found that A. adenophora invasion is associated with lower native species richness and correlated with lower tree canopy cover. Invaded soil and the proximity of A. adenophora leaf litter decreased seed germination rate of S. wallichii. Both invaded soil and leaf litter of the weed inhibited S. wallichii shoot and root biomass accumulation independently of each other. As far as we know, this is the first study to report these two effects simultaneously. In conclusion, belowground effects of A. adenophora invaded soil and airborne effects of leaf litter have a potential to inhibit native tree regeneration in Nepalese Schima–Alnus forests. Maintaining high canopy cover and removing litter of the weed should be tested to control its invasion.

众所周知，在亚热带亚洲，入侵性外来紫茎泽兰叶片凋落物中的挥发性化合物 会抑制本地物种的生长，但没有太多证据表明凋落物是否影响树木。特别是，很少探讨空气传播抑制与入侵土壤对树木的地下影响的相对重要性。我们使用紫茎泽兰未经入侵和入侵的土壤来追踪当地尼泊尔树Schima wallichii（DC。）Korth的发芽和幼苗生长。在有无紫茎泽兰叶凋落物的情况下。我们还比较了尼泊尔未入侵和入侵地点的本地物种的多样性。我们发现紫茎泽兰入侵与较低的本地物种丰富度相关，并与较低的树冠覆盖率相关。侵入和土壤的接近紫茎泽兰落叶层减少的种子发芽率S.蕨。杂草的入侵土壤和枯枝落叶都相互独立地抑制了瓦氏链球菌芽和根生物量的积累。据我们所知，这是第一个同时报告这两种作用的研究。总之，紫茎泽兰入侵土壤的地下作用和凋落物的空气传播作用都有可能抑制尼泊尔希马-阿尔努斯的天然树木再生森林。应测试保持较高的树冠覆盖率并清除杂草，以控制其入侵。