Uncovering Forests’ Tell-tale Fingerprints
Even to an expert, many commercial species of solid wood or veneer are often difficult to distinguish, sometimes between species, let alone by the origin. With new legislation governing timber trade coming to Europe and Australia and the existing US Lacey Act that bans imports of illegal wood, any methodology that would allow a purchaser to have greater confidence in the exact origin of a species that carries potential legal liability is welcome.
While DNA markers and chemical isotopes alone will not tell a purchaser or a prosecutor everything they need to know about a piece of timber or wood fibre, they can reveal a great deal about the origin or the declared origin of the material. Widely used in other applications, like matching DNA samples in forensic science or using chemical markers to determine the origin of agricultural products and food, applying genetic and isotopic fingerprinting techniques to timber would allow its origin to be checked independently from any documentation system.
“The benefits that genetic or isotopic fingerprinting offers to the forest products industry in verifying the true origin of timber is unparallelled at this time,” said Johannes Zahnen, GFTN-Germany Manager. “Standard methods for tracking timber, such as tags, ink and barcodes all have the potential to be tampered with or potentially forged, whereas these genetic or chemical markers are stored within the wood and cannot be altered.”
The German Ministry of Food, Agriculture and Consumer Protection are a firm supporter of the technology having seen it used increasingly within their jurisdiction. With ten years of development behind the technology there are now extensive “maps” of isotopes and genetics for major agricultural species—thanks to funding by the Ministry and commercial use by a number of German and other European retailers.
The isotopic technique compares various stable isotopes within the cellular structure of the wood fibre that is being tested. Based on reference samples, the test can reveal the likeliest match if a reference sample exists. If the origin has been declared and a reference sample exists for the declared origin, the probability of the sample coming from the declared location can be calculated.
On the other hand, the genetic technique examines the genetic variability within species. Trees do not move quickly, but they do move—at least their descendents move and carry certain genetic variations with them. The differences are not apparent to the naked eye, hence the consistency seen amongst large samples of timber of the same species. But to a geneticist with the right equipment, subtle variations can be identified.
For both systems, the degree of accuracy very much depends on the reference samples that can be compared. For species such as Swietenia (Big Leaf Mahogany), a reasonably complete map exists for the wild populations across Latin America. A relatively good map also exists for Cameroon, with GFTN Participant and forest concessionaire TRC having helped supply samples of Entandrophragma cylindricum (Sapele) and Iroko (Chlorophora excelsa).
With funding from the German Government set to continue for at least another two years, the role of isotope and genetic testing in origin verification looks set to grow. Biodiveristy International, based in Kuala Lumpur, is set to develop an open access database for reference materials in 2011. This should allow the various, and still limited, reference data sets to be drawn together to allow faster and cheaper comparisons of samples. In 2011, an ITTO project will commence across seven Congo Basin countries to develop reference material for future testing and analysis.
Accuracy is an issue for both systems, they need to be accurate to be of use commercially or by enforcement agencies but to be accurate more reference material is needed. Where there is good reference material the tests can narrow down an origin to within 200 kilometers with a high degree of confidence.
“Genetic and isotope testing alone are not a substitute for secure chains of custody supported by robust legal systems from the forest floor to the retail store,” said George White, Head of the GFTN. “However, they are a useful supplement in testing an assumption about the origin of a wood product. In a world where there are penalties for those who import illegal wood, knowing precisely where it came from is a great advantage—something that won’t be lost on those seeking to comply with the law or those looking to enforce it.”
For more information, contact:
Johannes Zahnen (firstname.lastname@example.org)