Herbal Remedy Threatens Medicinal Tree
Soaring demand for an herbal medicine is threatening the tree from which it is produced. The African evergreen tree Prunus africana, the source of an extract popular with people suffering from prostate disorders, is being felled at unprecedented rates, researchers say. Forestry experts have devised some techniques for boosting tree production, but they announced this week that the species could be extinct in the wild within 5 to 10 years.
Each year, Africa exports some 3500 metric tons of P. africana bark to satisfy a $220 million annual market. A bark extract known as pygeum is used widely in Europe and increasingly in the United States by men who believe it can ease symptoms of an enlarged prostate gland, although the evidence is sparse.
Pygeum can be harvested sustainably from wild trees by cutting off some bark and then letting it regrow for 8 years. But recently poachers have started stripping the bark entirely--which kills the tree--or cutting trees down. Domesticating the tree is a challenge, in part because seeds are hard to come by: The trees take 15 to 20 years to bear seeds, and the seeds don't live long.
Researchers with the International Centre for Research in Agroforestry (ICRAF), based in Nairobi, Kenya, have come up with some ways to make cultivation easier. They can preserve seeds for up to 2 years by drying them during the right stage of development and storing them carefully. The researchers also found that they could induce branches from a mature tree to take root themselves, thereby cutting the time it takes to produce seeds down to 3 years, says ICRAF geneticist Tony Simons. The team is transplanting seedlings to refuges and encouraging farmers to plant more trees.
Forest ecologist John Hall of the University of Wales says ICRAF's prediction of extinction in 5 to 10 years is too pessimistic, but he applauds the group's efforts. "There's no room for complacency," he says.