The growing trade in medicinal tree and shrub material in Kenya may be threatening many wild species. This will greatly impact more than two thirds of Kenyans who rely on traditional medicines for primary health care in a country where the doctor to patient ratio is 15 doctors per 100,000 patients.
A new study published in the scientific journal, Forests, Trees and Livelihoods has found that the material that supplies the Kenyan market is almost exclusively collected from the wild, making the traditional medicine industry unsustainable.
“It is largely unknown just how much is being collected and it could be far greater than previously thought, which raises serious concerns for the sustainability of natural resources,” says lead author Stepha McMullin, a Post-Doctoral Research Fellow with the World Agroforestry Centre.
It is estimated that 70 to 80 per cent of people in developing countries rely on traditional herbal medicines, and 70,000 tree and plant species are used worldwide.
For many smallholders in Kenya, the sale, processing and marketing of medicinal trees and shrubs is their only source of household income. The study shows that 60 per cent of traders had no additional income generating activities and 33% of traders reported earning more than KSh 14,000 (US $167) per month from the sale of medicinal plants.
“Greater consumer demand by a growing population with inadequate access to medical healthcare together with rural poverty is driving an increase in collection of medicinal plants from the wild, especially by women,” explains McMullin.
With a decreasing supply and virtually no sustainable sources, the opportunities for cultivation of medicinal trees and shrubs need to be explored. McMullin and colleagues gathered information on the previously undocumented trade in medicinal tree and shrub species in Kenya’s main city markets: Nairobi, Mombasa and Kisumu. Eleven markets in each city were surveyed and 91 traders interviewed to determine how the supply chain operates, which species are being traded, in what quantities and by whom.
The researchers identified 50 species botanically and a further 23 species were documented by their local names. The most commonly traded species was Warburgia ugandensis, known as the Greenheart, which is used to treat chest and stomach complaints, malaria, typhoid and amoeba. The Greenheart is common in Kenya in places such as the Aberdares, Cherangani, Chyulu, Karura, Mount Elgon, Rumuruti, Taita, Masai Mara and Baringo.
Traders either purchased their material from collectors or collected it themselves from natural forests, bush and woodlands.
The impact of the medicinal plant trade on wild populations largely depends on the part of the plant that is harvested. In the study, bark made up 51 per cent of material traded and roots 26.3 per cent. This raises particular concerns for sustainability given that techniques such as ring-barking and repeated bark stripping are used. Harvesting leaves is much less destructive but only made up 18 per cent or lower of the material traded in markets.
“If the trade can be documented, then further research and policy development could improve the value of these species not only for biodiversity conservation but also to benefit livelihoods,” says McMullin.
Considerable wastage also occurs during storage and processing. The plants which are collected are either sold individually or as part of a combination of materials used to treat specific diseases. They vary from raw materials to being crudely or finely processed. Overall, 50 per cent of the traders surveyed said the supply was not meeting current demand. When there is a deficit, they either find an alternative source, such as from different locations, or substitute another material, neither of which are sustainable solutions.
Over harvesting is a major cause of a decrease in the supply of medicinal plant material. According to traders other factors include; changing environmental conditions, greater restrictions on access to land, longer distances and more dangerous terrain that need to be travelled to source the material or a combination of factors.
“We found very little of the material was coming from sustainable cultivated sources,” outlines McMullin. “This is an area of enormous potential to both meet the growing demand as well as improve rural livelihoods.”
The study also showed significant differences regarding quantities and pricing of material between traders by location and gender. While 61 per cent of all traders were male, women did dominate the trade in Kisumu. In all of the markets surveyed, women traders collected larger quantities from the wild than their male counterparts.
“Further research to evaluate the threat to natural populations of selected priority species and to analyse the value chains for sustainable production and marketing is needed, “ says McMullin. “Importantly, the economic and ecological benefit of cultivating medicinal tree and shrub species on smallholder farms needs to be assessed.”
In other parts of Africa where the trade has been better documented, such as in South Africa, this has led to policy recommendations for improved value chains and sustainable production. Farmers in these countries are encouraged to grow medicinal plants in order to meet market demands that can’t be sustained by collection of medicinal material from the wild.
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McMullin S, Phelan J, Jamnadass R,Iiyama M,Franzel S, Nieuwenhuis M (2012) Trade in medicinal tree and shrub products in three urban centres in Kenya. Forests, trees and Livelihoods Volume 21, Issue 3