Can forensic science stop the felling of endangered wood? By Rebecca Prince

Have you ever looked at piece of furniture and wondered where the wood comes from? Did you realise that it could be the product of illegal trafficking? Rosewood is highly desirable and used to make beautiful furniture, but it is illegally logged which severely damages the environment. There is hope, however; forensics could help to stop this destructive trade.

Rosewood is a dark-reddish wood, but the term describes several different species of tropical hardwood. Dalbergia nigra, or Brazilian rosewood is one example. It makes for highly desirable furniture and grows in a number of southeast Asian countries such as Cambodia, as well as countries in Africa and South America.

Many species of rosewood tree are vulnerable or endangered according to the IUCN red list. Not only that, but the felling of these trees destroys the habitats of many other species that depend on them. We may be more aware of ivory or rhino horn trafficking, but in terms of value, seizures of rosewood vastly outweigh that of other wildlife products.

Countries have put legal restrictions on the wood, including bans on felling itself and exports of the wood. Some species of rosewood are also listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) which aims to protect wild animals and plants from international trade. However, rosewood continues to be illegally exported. Some protections, such as the EU timber regulations, prevent illegal rosewood being imported. In other countries, there is no such barrier once the wood has left its country of origin. China is an important market for rosewood and demand has grown in recent years. In 2014, rosewood imports to China were worth an estimated 2.6 billion US dollars.

Forensic science could help to identify and stop this trade, by checking whether or not a log is the type of wood it is claimed to be. Opportunities to access and test illegal wood arise at the points where illegal and legal supplies mix, including log yards, saw mills and importation.

With access to the wood, forensic tests can start. “Forensics” may make you think of DNA. This is one option but there are lots of other tests. Wood anatomists look at the structure of the wood, both with the naked eye and under the microscope. The microscope allows them to see the beautiful delicate patterns within the wood. This is useful in some circumstances, but many rosewoods are from the same genus – Dalbergi. Wood anatomy cannot tell the difference between the species within this grouping.

DNA could help solve this problem. One technology is DNA barcoding which compares specific sections of DNA. There is an issue with this: it is difficult to extract good-quality DNA from wood. But it can still help to find the source of illegal wood. In a study published in 2016, researchers found that they could tell whether rosewood was from Madagascar or not using DNA barcoding.

Another option is to study the chemicals that plants produce, known as phytochemicals. These can be detected using a technique called mass spectrometry. The research isn’t there yet, but it could be an effective tool. Phytochemicals can also help detector dogs to sniff out rosewood species.

In a recent study, researchers found that existing methods to investigate the true source of wood don’t seem to be working. They looked at furniture products sold in the US and found that many were not made of the wood they claimed to be. Forensic science has huge potential to change this, but the techniques need to be further explored and developed. Stopping the illegal trade could reduce deforestation and help preserve species and habitats. To do this, wood forensics need to move beyond the research world and be robust enough to stand up in a court of law.


Image: by jwvein from Pixabay

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