Abstract:
Population biology studies play a major role in understanding the ecology of our highly utilized natural
resources. Intense and frequent harvesting of bark from species with a high market demand often result
in ring-barking of trees. The trees subsequently die, and the species becomes rare over time.
Brackenridgea zanguebarica Oliv. is a species in demand not only because of its medicinal value but
also because it is highly regarded for its magical value. The species has a limited distribution and is
found only at Thengwe in the whole of South Africa. The population structure of the species was
investigated and the response of the species to harvesting pressure evaluated in order to gain an
understanding of its survival strategies. In spite of the high demand for the species it seems to be
surviving the harvesting pressure. B. zanguebarica showed a healthy population structure with lots of
seedlings. The adult individuals showed a very high degree of bark regeneration as a response to bark
removal from medicine men. The inverse J-shaped curve showed that the population is healthy
although sharp decreases between stem diameter size classes were observed. Fewer older individuals
have healthy crown covers since crown health status tends to decrease with increase in stem diameter.
It is therefore important to monitor the diameter size classes that are being impacted negatively by
medicinal bark harvesting for the population to remain viable at all times.
