Published in Jan 2020
Despite good intentions, some projects that have promoted alien tree species in the past have resulted in serious negative impacts.
• The risk of adverse effects can be reduced through review of funding or project proposals by multidisciplinary expert panels.
• Promotion of alien tree species should be subjected to rigorous risk assessment according to established international standards, particularly regarding their possible consequences for nature and nature’s contributions to people.
Planting of alien tree species has been and continues to be promoted, with the aim of addressing social and environmental problems in Eastern Africa. These species are promoted for agroforestry purposes, to re-green degraded landscapes or to alleviate fuel-wood shortages. Some of the pro-moted trees have spread widely and now cause serious environmental problems that impact human well-being, including losses of grazing land, reduced water availability and increased land management costs. We give recommendations to support decision making about funding for projects that aim to introduce new, or promote established alien woody plant species.