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Browsing Articles by Subject "Bark harvesting"
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Item Open Access Population biology of Brackenridgea zanguebarica in the presence of harvesting(Academica Journals, 2012-12-03) Tshisikhawe, Milingoni P.; Van Rooyen, Margaretha W.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.Item Open Access Population biology of Elaeodendron transvaalense Jacq. in the presence of harvesting(Fyton, 2013-01-12) Tshisikhawe, M. P.; Van Rooyen, M. W.Elaeodendron transvaalense Jacq. is one of the medicinal plant species commonly used by people in the Venda region. The species is known to treat a variety of diseases. It is widely used and important to traditional healers. Because of this, it found its way into the muthi markets, and it is among the seven most commonly traded plant species in the Venda region. This study investigated the impact of bark harvesting on the population structure of this species. The study revealed that although the level of bark harvesting is high, the species is able to resist that stress since it is a fine-grained species. The population also showed the ability to regenerate as it exhibited an inverse J-shaped curve. The crown health status was generally good although some individuals, contributing 9% of the sample, had dead crowns, which are a cause for concern. A linear relationship was noticed between areas harvested and stem circumference, which is understandable considering the large surface area of harvestable bark on bigger individuals.