IN MY taxi to the airport, the talk has turned to rainforests and whether cutting them down is bad. “Its not like here in the UK, where we know everything,” I say, waving at the soggy countryside. “I work in Brazil and we don’t know what’s in many forests. Cutting them down to grow soya can be a huge loss.”
That doesn’t impress the taxi driver, who left his country because of famine. I go on: “Then there’s all the medicinal plants in rainforests. If we hadn’t explored there, who knows what we would have missed out on – a cure for cancer?” This resonates. “My uncle died from cancer – maybe your forest could have saved him,” he says. “Perhaps everywhere should not be all about food.”
This argument is one that tropical biologists often wheel out. If you can’t convince people with a cute or curious flagship species, or by explaining the value of forests in stopping climate change, providing new foods or securing indigenous rights, then bring on the medicinal possibilities. It rarely fails.
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That’s because it’s true. Some childhood leukaemias are treatable thanks to vincristine and vinblastine, drugs deriving from the Madagascar periwinkle. And the active ingredients in curare are now used, not on blowdart tips, but in heart surgeries worldwide. Rainforest animals are also important. The skin exudates of Amazonian frogs have yielded blood pressure regulators, while venom from Asian forest scorpions and giant centipedes can help in neurological disorders.
But, as Robert Voeks says in The Ethnobotany of Eden, the real picture is a lot more complicated. Central to notions of rainforests as pharmacopoeia is what Voeks calls primitiveness, the idea that “primitive” can be equated with “purity” and purity with healing. This fuels the belief that we must preserve not just any old forest but the least contaminated, most Eden-like ones.
Voeks connects this “remote rainforest equals good” argument with medieval beliefs in unicorn horn, the curative powers of which supposedly stemmed from its purity and innocence. Modern research, of course, shows that Madagascar periwinkle grows at the edges of rainforests, and that many medicinal vines come from forests disturbed by humans or by a high incidence of tree fall. Moreover, provided they are not regularly burned, “secondary forests are just as likely to have pharmaceutically-useful plants as one shrouded in clouds, mystery, and isolation”, says Voeks.
“Secondary forests are as likely to have useful plants as one shrouded in clouds, mystery, and isolation”
Leading fieldwork seems to confirm this. In 2013, the veteran Amazon-based medicine hunter Adrian Pohlit told Â鶹´«Ă˝ that an extract from a common roadside weed is one of his best hopes for a new antimalarial drug.
Voeks is well equipped to write a book that readjusts perceptions. An ethnobotanist at California State University, Fullerton, he has spent 30 years in tropical locations such as Brazil and Borneo. There he has studied the medical uses of plants and their origins, and how other cultures (notably European and North American) perceive them.
Voeks’s students give him good ratings online for his ability to make the complicated clear and fun. They are right. His book is full of verve and enthusiasm, and he is eclectic, erudite and humorous as he ranges from the influence of the African diaspora, as they popularise their traditional medicines in the countries they now live in, to the meaning of kids’ eco-protest songs.
It is always right to celebrate indigenous medicinal knowledge and mourn its loss. But Voeks’s challenge to the West’s muddled and dangerously romantic views of rainforests as phytomedical cornucopias and sources of near-mystical “purity” for drugs is what singles his book out.
University of Chicago Press
This article appeared in print under the headline “Get real about rainforests”
