SPECIAL REPORT – Seeing the wood through the trees *

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* From time to time we’ll post a special report, which will be longer than our normal posts.

See also The Economist, 22nd September 2012.

Illegal logging is a major contributor to tropical deforestation and forest degradation. Aside from clear advancements in establishing protected areas and sustainable certified forestry, forest loss still proceeds at great speed. Between 14 and 16 million hectares of forest are lost each year, most of which is in tropical regions. Internationally the illegal logging industry is estimated at $30 billion annually, and again is disproportionately active in tropical countries, although far eastern Russian is also an area of significant concern.

Beyond simple forest loss and associated extinction of species, deforestation also contributes to global warming, contributing between 20 and 25% of global CO2 emissions. For example in Indonesia, one of the world’s largest CO2 emitters behind the USA and China, and a country with significant illegal logging problems, more than 80% of CO2 emissions result from deforestation (Degen B, Ed., 2008. Proceedings of the international workshop “Fingerprinting methods for the identification of timber origins” October 8–9 2007, Bonn/Germany. Landbauforschung, vTI Agriculture and ForestryResearch, Sonderheft 321, Germany).

Recognising that illegal logging has a range of serious and broad ranging environmental impacts, legislation has been introduced to limit the importation of timber from non-certified or illegal sources in the US (The Lacey act), EU (FLEGT and EUTR), and is currently being debated for introduction in Australia. Details of this legislation have been covered recently in The Conversation here and here.

Some of this legislation now has real teeth.  Originally passed in 1900 to limit trade in a range of illegal wildlife goods, the Lacey Act was extended in 2008 to include timber products. It requires any U.S. company importing exotic wood products to take extra care in documenting sources and confirming they aren’t in violation of global sustainable forestry practices.

Earlier this year the U.S. Department of Justice reached a criminal enforcement agreement with Gibson Guitar, a high profile producer of guitars, resolving two investigations into allegations of importing illegally harvested wood materials into the United States from Madagascar and India.

Whilst not prosecuted criminally, Gibson “acknowledged that it did not act on prior knowledge that legal ebony was difficult or impossible to source from Madagascar”, that the investigation into the harvest and export of these woods “served important environmental and law enforcement objectives,” and that its duties under the amended Lacey Act include “reasonable corroboration of the circumstances” of the harvest and export of musical instrument parts from foreign countries.”

Gibson were required to pay a penalty of $300,000, as well as $50,000 to the National Fish and Wildlife Foundation to be used “to promote the conservation, identification and propagation of protected tree species used in the musical instrument industry and the forests where those species are found.” In addition, the company was required to implement a detailed compliance program and relinquish its claim to the seized wood.

The case received broad coverage, and is widely held up as the first instance of action taken to enforce the Lacey Act’s provision for wood sourcing. This is a clear message to American manufacturers and importers that the government means business when it comes to illegal logging (see “Gibson and the Lacey Act – a game changer in the music industry”).

Aside from such cases involving trade-restricted species, how can we be sure our timber comes from a legal source? Credible voluntary certification, such as the FSC (Forest Stewardship Council), are one such way. However the practical checks in place to monitor the flow of legal vs illegal timber are not tamper-proof. Commonly used are “Chain-of-Custody” methods which seek to assign a paper identification to individual logs that can be tracked along the timber supply chain, from logging concession to producers. However these ‘paper passports’ are open to falsification, particularly between the logging concession and mill, where most illegally logged timber is introduced into the supply chain.

Fortunately there are a number of methods that can be applied to verify source claims, the most promising of which are from a suite of DNA-based methods; DNA fingerprinting, genographic analysis and DNA barcoding.

Scale of resolution of different molecular genetic and non-DNA techniques from species identification, through regional and population provenancing to individual log tracking (Lowe AJ, Cross HB (2011) The Application of DNA to Timber Tracking and Origin Verification. Journal of the International Association of Wood Anatomists 32(2): 251-262.)

Species identification and DNA barcoding

DNA barcoding is a global initiative designed to standardise genetic species identification through the analysis of short DNA sequences (Hebert et al. 2003). DNA barcoding, as facilitated by the Consortium for the Barcode of Life (CBOL) and the International Barcode of Life Project (iBOL), has developed a standardized set of gene regions and central database of reference samples (Barcode of Life Database – BOLD) to identify many species around the world.

For DNA barcoding of plants, one of the biggest challenges has been to identify a gene region that could effectively and reliably differentiate between species. Only resolved in 2009, the CBOL Plant Working Group finally recommended a combination of two chloroplast genes, maturase K (matK) and ribulose-bisphosphate carboxylase (rbcL). A combination of these two genes is estimated to distinguish 70% of all plant species, although applications in the field can be higher (Costion C, Ford A, Cross H, Crayn D, Harrington M, LoweAJ (2011) Plant DNA barcodes can accurately estimate species richness in poorly known floras. PLoS ONE 6(11): e26841.

If further species resolution is required, ‘local’ barcodes can be developed. For example, a set of local barcodes were successfully developed to differentiate between the three species of mahogany from Central America, when the standard barcode genes failed to tell them apart (Muellner, A.N., H. Schaefer & R. Lahaye. 2011. Evaluation of candidate DNA barcoding loci for economically important timber species of the mahogany family (Meliaceae). Mol. Ecol. Resources.

A DNA barcoding approach would have been able to identify that the wood sourced by Gibson Guitar came from a restricted species.

Source origin and genographic mapping

For many species protected under CITES, country of harvest is critical to determining the legality of timber. However, the application of genetic methods requires that genetic structure is present across region of interest. Genetic variation can be structured at a continental scale due to geological events or climatic gradients, at population scales due to gene flow limitations and genetic drift, and at individual levels due to mating systems, seed dispersal syndromes and selection gradients. These interactions will produce genetic discontinuities that can be mapped (genographic mapping).

In a nice early example of the power of such methods, an angler was disqualified from a fishing competition when molecular tests on the fish presented to officials identified that it could not have come from the river system where the competition took place (Primmer, C.R., M.T. Koskinen & J. Piironen. 2000. The one that did not get away: individual assignment using microsatellite data detects a case of fishing competition fraud. Proc. Roy. Soc. Lond. B: Biological Sciences 267: 1699–1704.). When presented with this evidence, the angler confessed he had purchased the winning fish from a local market.

For timber, a blind test (one where the testing lab does not know the origin of samples) was performed using a genographic map developed for mahogany. The testing of blind samples was coordinated by the World Wildlife Fund for Nature (WWF) and the testing lab was able to correctly assign wood samples to a Bolivian or Guatemalan source with a high degree of certainty (>98%, Bernd).

Individual tracking and DNA fingerprinting

DNA fingerprinting, a set of markers similar to those used in human forensics cases, has been applied commercially for several years to track timber logs along supply chains, from timber concession to mill, the stage most prone to the substitution of illegally harvested timber and where falsification of documents certifying origin is rampant.

In a study of merbau, Intsia palembanica, a high-value timber species from southeast Asia used for decking, DNA fingerprinting was used to compare samples of timber from a saw mill in Java, Indonesia, with their declared forest source (Lowe et al. 2010). In this test, all mill samples could be positively identified as coming from the forest concession and not from another source, good news for Simmonds Timber, who market their DNA-verified product as ‘DNA lumber’ (study featured in a recent UNEP/INTERPOL report).

DNA extraction from wood

One of the key problems with applying genetic tests to wood is actually extracting DNA from test samples in the first place. Overall, the challenges with using wood for genetic work are twofold: both the quantity and quality of the DNA are low. However using contamination-exclusion techniques originally developed to work on ancient sources (such as wooly mammoths and Neanderthal man), it has been possible to apply DNA tests to timber that is up to 3600 years old. Therefore, if DNA analysis is undertaken using processes that reduce contamination, there is no reason why DNA analysis of timber should not become routine.


Molecular genetic methods are now set to supplement or in some cases replace other methods that have been used to verify source. For example, wood anatomy has been applied for many years to species identification problems, but is commonly unable to resolve down to the species level, although analytical chemistry may be employed to identify particular target species. Isotope analysis, commonly used to verify the source of food and drink, has recently also been successfully applied to verify timber origin, although cannot be used to distinguish between species or fine geographic scales (i.e. between logging concessions). And timber log marking (e.g RFID tags), sometimes used to follow supply chains, can only be applied to individual logs at the time of felling, limiting their downstream application to supply chains.

The advancement of genetic technologies means that large-scale DNA screening can now be done cheaply, quickly and with a statistical certainty that can be used in a court of law. This now means there are an increasingly powerful array of methods that provide the consumer with a verifiable confirmation of the declared source of origin of timber products, so that they can actively chose to use timber products that aren’t illegally sourced and contributing to the global deforestation crisis.

Further reading:

Lowe AJ, Cross HB (2011) The Application of DNA to Timber Tracking and Origin Verification. Journal of the International Association of Wood Anatomists 32(2): 251-262.

[Featured image: Photo by Khari Hayden on Pexels.com]


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