The ITTO (International Timber Trade Organisation) project was a three-year collaboration between the Thünen Institute of Forest Genetics and 14 other laboratories/agencies in order to develop and implement a timber tracking system using stable isotope testing and DNA testing for three species of tree – Iroko (Milicia excelsa + M. regia), Sapelli (Entandrophragma cylindricum) and Ayous (Triplochiton scleroxylon) – in seven African countries (identified due to being areas of tropical timber significance).
Reference databases and maps were created for each species of tree. Agroiosolab GmbH was responsible for the development and production of the database for Iroko (Milicia excelsa).
Over 470 reference samples of Iroko were taken from Cameroon, Democratic Republic of Congo, Gabon, Ghana, Ivory coast, Kenya and the Republic of the Congo, with the latitude and longitude coordinates recorded. The samples were then analysed, and the results of the stable isotope test below.
The sampling was carried out by a team from the Gembloux Agro-Bio Tech, based in Belgium, who had experience sampling in West and Central Africa. The project included logging companies and forest authorities in the different African countries to subdue any reservations about the techniques and tools used, as well as that results from the blind tests, carried out to validate the approaches for species identity, country of origin and chain of custody, would ensure support of the methods used - an important factor in the project.
Agroisolab GmbH stable isotope data for Iroko (Milicia excelsa + M. regia) from African countries for ITTO project
As seen in the table, the isotopes analysed consisted of oxygen, hydrogen, carbon, nitrogen, sulphur, and the higher isotope of strontium – three additional isotopes as outlined in the ITTO project in order to differentiate on a regional level, allowing for more accurate results.