Double jeopardy: bark harvest for malaria treatment and poor regeneration threaten tree population in a tropical forest of Uganda

Several forest plants known to supply medicine are under pressure worldwide. We carried out a study of four tree species (Warburgia ugandensis Sprague, Fleroya rubrostipulata (K.Schum.) Y.F.Deng, Syzygium guineense DC. and Zanthoxylum chalybeum Engl.) that are highly demanded for malaria treatment. The study was undertaken between 2006 and 2009 in the Sango Bay Forest Reserve, southern Uganda. The aim was to determine the conservation status of trees targeted for malaria treatment. We assessed the level of damage inflicted on trees during harvesting of medicinal parts and determined the population density of target species in the forest. We used 95 plots established along nineteen transects. Survival of the most preferred species, F. rubrostipulata, is of particular concern as its population suffered from a combination of extensive damage due to poor methods of harvesting and poor regeneration. The density of trees with diameter ≥5 cm differed between species and sites, demonstrating different recruitment and survival strategies. Management of Protected Areas should augment strategies to monitor the legal and illegal harvest of medicinal plants, by adopting low impact harvesting methods, and designating the temporal and spatial patterns of harvesting. This might reduce tree damage and mortality.