Catha Edulis: a threatened tree in the West Usambara Mountains, Tanzania

Assessment of the effects of stimulant trade on the future survival of Catha edulis trees was conducted in the West Usambara Mountains. A total of 65 plots of 0.1 ha each were established along two transects. All C. edulis trees in each plot were counted and recorded based on their health status. Of the 350 sampled trees, only 12% were healthy whereas 88% were either damaged or dead or dying. The number of C. edulis trees in the plots reflected a similar situation to trees outside the plots. Health distribution for diameter classes revealed that leafy harvesting had more impact on large trees as compared with small trees. About 93% of all healthy trees had diameter class less than 20 cm. While 86% of all damaged trees had diameter class above 20 cm, no dead trees with diameter class less than 20 cm were recorded. This indicated that most leaves of large old trees were preferred compared with those of small and young trees. However, due to scarcity of leaves from large trees, leaves from regenerated seedlings were also harvested. Thus, in the absence of conservation efforts, C. edulis faces danger of extinction