Scientists use DNA testing to help reduce the illegal export of endangered medicine tree

Cameroon forest aerial photo

Forest equates for more than 40% of Cameroon's total land area
Image by CIFOR (CC BY-NC-ND 2.0)

University of Adelaide scientists are helping reduce the worldwide illegal export of timber, by testing for genetic variation between populations of the endangered African Cherry tree.

Scientists from the Advanced DNA Identification and Forensics Facility at the University of Adelaide have teamed up with the Ministry of Forestry in Cameroon, University of Douala’s Faculty of Sciences, and DoubleHelix (Singapore). The partnership is funded by the International Tropical Timber Organization (ITTO).

DNA testing is now being increasingly utilised to help bring an end to environmental crime or at least to reduce the level of illegal trade. The latest focus of attention is the endangered African cherry – Prunus africana. Its bark, which has medicinal properties, is a valuable extract used by European pharmaceutical companies in the treatment of prostate disorders.

This valuable tree first came to the attention of CITES – the Convention on International Trade in Endangered Species of Wild Fauna and Flora – back in 1995 when it posted an alert to restrict the trade in the bark of African cherry, which was becoming endangered.

CITES aims to ensure that international trade in specimens of wild animals and plants does not threaten their survival in the wild. The organisation joined forces with the International Tropical Timber Organization (ITTO), and during the ITTO-CITES Programme (2006-2016) provided assistance to countries to implement CITES provisions for tropical tree species. CITES continues that work with the current CITES Tree Species Programme that was launched in 2017, and to which ITTO remains as a robust collaborative partner.

The main conservation concern with the African cherry tree is around the harvesting of its bark. While the tree is resilient to some bark removal, poor practises and excessive bark stripping leads to death of the tree. Such practices have led to the African cherry being classified as “vulnerable” by the International Union for Conservation of Nature (IUCN) on their Red List and is listed under Appendix II of CITES – which means trade must be controlled in order to avoid utilisation incompatible with the species’ survival.

While the extent of threat to the survival of the species has been contested, in 2006 the CITES Plants Committee expressed heightened concern over the decline of populations in Burundi, Cameroon, the Democratic Republic of the Congo, Equatorial Guinea, Kenya, Madagascar, and Tanzania.

After years of unregulated trade and over-harvesting, the EU imposed an import ban in 2007.

In Cameroon, an ITTO-CITES programme of work began in 2009 to introduce sustainable management, starting with an inventory of African cherry trees and to document the level of harvesting.

The project established controlled sustainable harvesting in the main production areas of Cameroon, as well as in other African countries, like the Democratic Republic of the Congo. This work allowed Cameroon to produce the “Non-Detriment Finding” required by CITES, after which a conservative export quota was approved by CITES, allowing trade to recommence. This project also tackled problems associated with bark being taken from uncontrolled areas and mixed with product from controlled areas, which had been approved in management plans.

The work was coordinated by ITTO-CITES Programme Regional Coordinator in Africa, Professor Jean Lagarde Betti, who was able to tap into the large network of stakeholders (Government officials, private sector and local communities), brought together to deal with CITES listed tree species in the region since 2008.

The work was undertaken in two phases. Phase 1 involved building inventories, developing simple management plans, setting annual quotas and development of non-detrimental findings (2008-2012). Phase 2 involved the implementation of management plans and recommendations of the non-detrimental findings (2012-2015).

For the second stage of the work in Cameroon, ITTO-CITES needed help to set up a DNA verification system for Prunus africana.

In 2014, Double Helix Tracking Technologies was called on to coordinate exploratory work on the genetic variation of the African cherry, which was scattered across the mountain ranges of tropical Africa and Madagascar.

In partnership with the Advanced DNA Identification and Forensics Facility at the University of Adelaide, a major avenue of work was undertaken to understand if it was possible to differentiate between bark from controlled and uncontrolled harvest areas, and so identify and exclude uncontrolled, unsustainable supply from the market.

University of Adelaide researcher Professor Andrew Lowe said “we used the latest genomics methods to develop and apply a simple DNA test for African cherry".

"The initial scientific results showed significant genetic variation between populations – even those less than 10 km apart.

"These results are tremendously promising and warrant further investigation, particularly to establish if differences can be identified at the annual plot level."

“It’s also particularly important that this DNA work supports the implementation of simple management plans, and that local staff are trained in sampling and analysis procedures”, explains Professor Lowe.

One man on the ground in Africa, who worked on this project and collected a lot of useful information, and knows all about the problems with African cherry trees, is Germain Yene, the Regional Coordinator for DoubleHelix.

Did Germain encounter any resistance to his work in helping to manage the African cherry bark according to CITES rules?

“In the field, we took samples at different points in the supply chain from batches of bark in the field to products prepared for sale or export," says Germain.

"Interestingly the sampling teams collecting bark did not encounter any resistance from the local people, only curiosity.”

Germain also pointed out that the areas open to the exploitation of Prunus africana tend to be natural forests, where the species has been growing naturally.

“However, there are local people in some areas who have planted Prunus and can seek to sell it by mixing it with the bark from the sites authorised for harvesting," he says.

"It was made clear to all concerned that this work was being supervised by the administration in charge of forests and the environment to support CITES requirements, and which therefore had the potential to support good business operators."

But he admitted that it can be risky work. Germain recounted that in the Lake Kivu region of the Democratic Republic of Congo, the local sampling team once came face to face with armed rebels “who confiscated their samples and working equipment”, but no one was harmed in the encounter.

The next phase of the project, a partnership funded by ITTO between the University of Adelaide (Australia), the Ministry of Forestry in Cameroon, the Faculty of Sciences of University of Douala and DoubleHelix (Singapore), is expected to start in Cameroon next month (May 2021) and involves four key objectives:

  • Implementing an effective DNA traceability system to control trade in Prunus africana, as well as Pericopsis elata - commonly known as African teak.
  • Collecting samples of P. africana and P. elata from different populations in Cameroon.
  • Developing new genetic markers for P. africana, suitable to differentiate between populations in neighbouring areas.
  • Analysing all samples with genetic markers to determine the most appropriate level of discrimination at different population levels for each species, such as “Prunus Allocation Units” or annual harvesting plots.

Working under the supervision of the Ministry of Forestry and the Faculty of Sciences of University of Douala, Germain’s role will once again be to coordinate the collection of samples from across Cameroon. He will also check that the samples are of sufficient quality before they are sent to the laboratory at the University of Adelaide.

Since it has been over five years since the first project was completed, more training of local teams will be required

“Among other selection criteria, it will be necessary to have a good knowledge of the species – its ecology and distribution. When it comes to implementation of a DNA verification system, it is also a question of identifying the different handling points for samples and products along the supply chain, from the forest to the port of embarkation,” Germain says.

“We will take a random assortment of bark and product samples, which will be compared to the genetic reference database to verify that they are from the claimed harvest area or not. “

Germain says we should think of it as a quality control system, but instead of checking for the physical quality of the bark, he is checking for the quality of its environmental claims.

Overseeing the collaborative project in Cameroon, Professor Betti sees this advanced DNA traceability project as essential to stop the depletion of endangered tree species and to control the trade in Prunus africana, as well as Pericopsis elata.

“While we accept that the African cherry has important international value as a medicine, we must find a way to stop the illegal harvesting of its bark. Of course, the tree is resilient to some bark removal, but poor and excessive bark stripping leads to death of the tree. This must stop,” Professor Betti insists.

The project is the latest in a series supported by the ITTO, focusing on the development of DNA techniques for timber traceability.

ITTO’s Steve Johnson, who oversees work with CITES, noted that reliable tracking of products from CITES-listed species, such as the African cherry tree, is essential for assuring the global community, importers and other stakeholders that trade is sustainable and not detrimental to the long-term survival of the species.

“We are pleased to be working, once again, with the Government of Cameroon, as well as with our experienced colleagues from the University of Adelaide and DoubleHelix, to help to ensure that the trade in sustainably-produced

Prunus bark continues, so that the medicines produced from it continue to alleviate the suffering of prostate patients around the world,” Mr Johnson stated.

DNA traceability systems were first introduced by DoubleHelix in the Indonesian forestry sector in 2007, designed to verify Chain-of-Custody documentation of Merbau wood, processed for export to Australia, New Zealand and Europe, work that was also supported by ITTO.

Tagged in Research, Engagement and Industry, School of Biological Sciences, Genetics, Ecology, Evolutionary Biology

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