Environment

A Tree That Saves Us From Cancer Is Dying Out In Nepal

The skyrocketing demand for a highly effective anticancer drug is leading to the demise of a yew tree in Nepal. The Taxus mairei, one of the three species of yew trees growing in Nepal, is critically endangered in the country. It yields a compound called 'taxol' that is a proven anti-cancer agent. Realizing the need to protect the fast-disappearing Maire's yew tree, a team of conservationists led by Kumar Paudel and Reshu Bashyal from Greenhood Nepal launched a project in 2018 to estimate its population in Nepal and engage the local community in its conservation. Their study revealed some shocking facts. World Atlas spoke with Kumar Paudel, Co-founder and Director at Greenhood Nepal to learn more.

A Valuable Tree On The Verge 

Taxus harvester segregating the leaves soon after harvest. Image credit: Kumar Paudel/Greenhood Nepal

In Nepal, yew trees have been traditionally harvested for a variety of needs and more recently, to cater to the increasing demands of the modern pharmaceutical industry. These trees are famed for the compound taxol that is present in their leaves, barks, and trunks. The compound is extracted from these trees to produce a drug that is used in cancer treatment. Although yew trees are also cultivated, wild trees are not spared for taxol extraction. Experts warn that the world cannot afford to lose the wild gene pool of this tree. The latter is always of greater significance as it is more diverse and associated with robust populations that can withstand stress better than their "pampered" cultivated counterparts.

A group of women harvesters entering the forest in Kavrepalnchok, Nepal. Image credit: Kumar Paudel/Greenhood Nepal

Given the unregulated exploitation of wild yew trees and little studies existing to warn conservationists of their conservation status, Paudel and his team decided to investigate the matter further. Here is what first drew Greenhood Nepal's attention to the country's yew trees:

"We had seen people harvesting yews while visiting communities during the pangolin field research in Kavrepalachok, Nepal. Looking at the exploitation of these trees, we had some doubts about their survival in the wild. Meanwhile, in 2017, I saw yews widespread in Oxford, UK, and that was different than what I had seen in Nepal. These incidents stimulated my passion to learn more about the yews of Nepal," said Paudel, Co-founder and Director of Greenhood Nepal, a non-profit organization driven by science that concentrates on human dimensions of nature conservation.

In Need Of Urgent Conservation

Greenhood researcher collecting data in the field. Photo: Reshu Bashyal/Greenhood Nepal

As the Greenhood Nepal team started examining the conservation status of the yews of Nepal, they understood that proper evaluation of their population, especially that of the Taxus mairei species, was urgently needed. Hence, they launched a project in 2018 with advisory support from the Interdisciplinary Centre for Conservation Science, University of Oxford, to estimate the wild population of the species in Nepal and to learn about the impact of the harvesting methods used by local communities on these trees. The results of the study revealed some concerning facts.

"Our study showed that only a few hundred of Maire’s yew trees (except seedlings and saplings) are left in the wild in Nepal. However, the propagation and cultivation of these trees in private lands are increasing due to high market demands," informed Paudel.

 A nursery person showing a propagated Taxus mairei in his Nursery, Nepal. Image credit: Kumar Paudel/Greenhood Nepal

The study also found that the tree had restricted distribution limited to only three districts of Sindhuli, Makwanpur, and Kavreplanchowk in Central Nepal. The researchers suggested that long-term unsustainable harvesting of these trees in the absence of proper guidelines is the possible cause of such low numbers. They also exhibited concern over the fact that these trees are now being propagated by the stem cutting method affecting their genetic diversity.

"Maire’s yew is one of the 13 species of yews worldwide. Among that Nepal hosts three species - Taxus mairei, Taxus contorta, and Taxus wallichiana. These species are among the most exploited medicinal plants in Nepal. Unlike the other two species, Taxus mairei is nationally critically endangered and reported from only three districts of Central Nepal. Uncontrolled harvest can lead to the extinction of the species in the wild in the country as there are not many of them left," warned Paudel.

Greenhood researchers consulting with a local nursery in Kavrepalanchok to understand their propagation and cultivation practises. Image credit: Kumar Paudel/Greenhood Nepal

Given the severe issues threatening Maire's yew tree in Nepal, it is evident that urgent and necessary actions need to be implemented to protect them in the country. Paudel and his team are working in the direction to ensure the same.

 "Greenhood Nepal is working for the long term survival of the wild Taxus mairei in Nepal. We have estimated the wild population and drafted sustainable harvesting guidelines. We are working with communities to train them to practice the sustainable harvesting method in a way that is beneficial to both the yews and the communities," he said.

While the Maire's yew tree may be saved just in time, there are many species of flora on the brink around the world. Often, they go ignored, due to a phenomenon called "plant blindness" that leads to limited attention given to plant conservation. However, there can be no argument on the fact that plants are important for both environmental and human health. The faster the world realizes this, the better it is for the future generations of the planet.

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