One of Africa's unique trees, Prunus africana, is threatened with extinction due to demand in Europe and America for a medicinal extract produced from its bark.

By Judith Achieng

May 1999

The tree popularly known as Pygeum or Prunus africana is the only African variety of more than 200 species of Prunus scattered around the world and the only one used by pharmaceutical companies to manufacture a drug used in treating prostrate problems among elderly men.

'Prunus africana was once well distributed throughout Africa, from Ethiopia to South Africa and from the west coast to the island of Madagascar. Since its medicinal properties became widely known, it has been ruthlessly harvested,' said Tony Simmons, a researcher at the Nairobi-based International Centre for Research in Agroforestry (ICRAF).

Simmons said nearly 60% of men over 50 in Europe and America suffer from prostrate-related diseases, putting a demand on the production of drugs obtained only from the dark trunk of the evergreen tree found only in Africa's scattered mountainous regions.

The bark is currently priced at $220 million in the pharmaceutical industry, from an annual average harvest of 3,500 tonnes, fetching up to $60 per kilogramme.

'With rising incidences of prostrate problems, an aging population, and a growing confidence in natural medicines, some companies believe the market for prunus remedies could double or triple in the coming decade,' he told a conference on the plant which brought together international forestry experts and commercial interests in the capital Nairobi in late September 1998.

All that is left of the tree, which usually grows over a period of 30 years to stand up to 40 metres tall, is a limited number of wild populations mainly in Kenya, Uganda and the Democratic Republic of Congo (DRC) where moderately sized natural stands of the tree still exist.

The conference heard that in the north-western province of Cameroon and also the Indian Ocean island of Madagascar, the tree is now faced with extinction.

'Prunus was a common tree in Cameroon, but now it is scarce, due to unsustainable harvesting,' said Christian Asanga, who works for the Cameroonian government's department of forestry.

Scientists say the tree, which has been used for centuries by African traditional healers to treat similar problems, in addition to a range of diseases, was harvested in a sensible manner until commercial interest came in. 'You will hardly find any concoction from a traditional healer which does not have Prunus africana,' Asanga explained.

'But they only removed small panels of the bark from standing trees, leaving others to nourish the tree while the removed portion heals,' he said.

As demand grew, however, larger quantities of the bark were stripped from standing or felled trees. Generally, trees were stripped 'naked' as with the case of Mount Cameroon, where up to 8,000 trees were left dead but standing. In the Mount Kilimindie region (also in Cameroon), 80% of mature trees died as a result of poor harvesting techniques, Asanga said.

A few years ago, Prunus africana was appended to the Appendix II list of the Convention on International Trade in Endangered Species (CITES), which only allows licensed trade of products from the tree.

But even this has done little to stop illegal exporters in Cameroon from overexploiting the tree. They come to villages at night and bribe the people into giving them permission to harvest the bark, says Asanga. In Kenya, unlike in Cameroon, the tree, which also has a good market for timber and fuel, is threatened by renewed demand for human settlements, while large chunks of forests continue to be cleared.

Stella Simiya of the National Museums of Kenya (NMK) told the conference that although most Kenyans are aware of its medicinal values, the tree is fast disappearing, to make way for settlements. At most, Simiya said, Prunus africana will last 10 years in Kenya.

In Uganda, there are few traces of the tree left in the southern Kabale hills, where it was until recently in abundance, mainly due to over-cultivation, according to Wilson Bamwerinde of Uganda's forestry department.

Jonathan Leakey, Kenya's only harvester who exports his bark to a pharmaceutical company in France, is also concerned. 'My interest is to be able to see continuing harvesting of the bark for commercial purposes, but there is a limited amount of forest in this country and the cutting of trees cannot go on forever,' says Leakey, who earns $2 per kilogramme of bark. His average annual harvest and export is 400 tonnes of bark.

Kate Schreckenberg, a senior fellow at the London-based Overseas Development Institute (ODI), urged farmers to replant the trees.

'We are asking ourselves what kind of money farmers can earn from growing the tree and whether there are markets out there to sustain them,' she said. Currently, the whole bark of a 40-metre-tall tree can earn as much as $500, a sum which Schreckenberg says is too little considering the tree takes up to 20 years to start producing decent bark and up to five years for the bark to heal after removal. 'Benefits from the tree must be shared equitably, trickling down to the farmers,' she said.

Prunus is cultivated in mountainous areas where most farmers usually prefer to grow cash crops such as coffee, tea and pyrethrum. - Third World Network Features/IPS

About the writer: Judith Achieng is a correspondent for Inter Press Service, with whose permission the above article is reprinted.