Project

Identification of timbers in international traded charcoal

Lead Institute HF Institute of Wood Research

Grilling with charcoal is the trend. According to figures from the German Federal Statistical Office, consumption in Germany in 2016 was 250,000 tonnes – and rising. Most of the wood used does not come from "domestic forests". Around 85 % of the sold charcoal is imported from abroad, often from tropical and subtropical regions, but also from Eastern European forests.

Background and Objective

Since 2016, several consumer and environmental protection organizations have asked the Competence Centre to test charcoal batches that are commercially available in supermarkets, petrol stations or DIY stores.

The anatomical examinations serve a clear identification of the processed timbers and to verify the compliance of declarations of timber species and the stated origin of the timbers on the packaging. Overall, the investigations make an important contribution to quality assurance and consumer protection and generate important datas for understanding the flow of goods in the international charcoal trade

Approach

For the determination of the selected charcoal/briquette samples, a special 3D reflected light microscopy technique was used to display the characteristic anatomical structural features. In contrast to the microscopic determination of solid woods, charcoal cannot be prepared as flat (planar) cut samples, as the structure is strongly decomposed by the charring process and is very brittle. With the help of the new digital microscopy technique, the uneven areas within a programmable field are digitally scanned and assembled.

Preliminary Results

In a study, carried out in 2017 on behalf of the WWF, revealed:

Approximately 50 % of the assortments traded in Germany did not contain any information on the woods or tree species used,
only 30 % of the charcoal and briquettes came from certified sources (FSC or PEFC),
About 40 % of the assortments traded in Germany mainly contained wood from subtropical or tropical regions. Three-quarters of these consisted exclusively of tropical/subtropical woods, while in one-quarter these woods were added to woods from temperate latitudes.

Further comprehensive test orders have followed to this day. The investigantions of about 450 assortments and about 6,750 microscopically analysed individual samples have provided basic knowledge about the used woods and deviations from the declarations.