An estimated 50,000 plant species are used medicinally, with global trade exceeding $60 billion per year. Within the plant kingdom, trees make a substantial contribution to this figure and many species are used in traditional and modern medicine.
Medicine from trees, extracted from the wood, bark, roots, leaves, flowers, fruits or seeds is fundamental to the well-being of millions of people. Where access to modern pharmaceuticals is limited, trees offer living pharmacies open to anyone with traditional knowledge on their medicinal properties.
Medicine from trees is also traded internationally, with many prescription drugs based on molecules taken from trees. Certain trees, such as the North American witch hazel (Hamamelis virginiana), are cultivated to meet demand for its medicinal properties whereas medicine from other species is harvested directly from wild populations.
Sustainable extraction of medicine from wild trees can provide an economic value to conserve forests and the medicinal trees within them. However, without careful management, over-exploitation, driven by strong market demand, poses a significant threat to many trees. Below we highlight just a few of these species.
This tree is found in montane tropical forests across central and southern Africa and Madagascar. Its bark is used locally and traded internationally to cure malaria, fever, kidney disease, urinary tract infections and prostate cancer.
International trade, between range states, France, Italy and Spain is estimated to exceed $200 million annually although there are signs that the species is now struggling to sustain the demand. Harmful extraction methods are causing the species to decline across its range.
Endemic to the island of Cebu, in the Philippines, this species also has a bark with medicinal properties. Its main users are local residents who use the bark as a remedy for stomach ache by either chewing it directly or boiling it with a glass of water before intake.
Harmful extraction methods lead to infection and death of mature trees and wider deforestation on the island has led to the species becoming Critically Endangered.
The species yields a bright red resin known as ‘Dragon blood’ used and traded by the Roman empire as a pigment and as a medicine as early as the 1st Century BC. Endemic to the island of Socotra, near Yemen, today, local people still use it to cure a range of ailments including diarrhoea, fever and dysentery.
The Himalayan yew (Taxus contorta)
All yew species are used to produce Taxol, a chemotherapy drug to treat cancer. This species, found in Afghanistan, India and Nepal, is threatened by over-harvesting for medicinal use and collection for fuel.