Subsidient: Laura van Gilst/Wageningen University
Subsidy: S20.1-69

Several methods exists to identify species and possibly trace the geographic origin of (woody) plants. However, the potential of chemical methods such as multi-element analysis of timber, is still largely unknown. In this thesis, multi-element analysis by means of ICP-MS was used to examine the potential to differentiate three locations in the south of Cameroon based on the element concentrations in the heartwood of Lophira alata (Azobé). For 24 elements the data obtained on the element concentrations of the wood, was used to calculate Transfer Factors (TFs) from sapwood to heartwood and to perform statistical analyses. When comparing the element concentrations in the heartwood between the three locations, it was found that the elements Si, Mg, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd, Cs and La showed differences between at least one pair of locations. Ni was the only element able to distinguish all three locations. It can be concluded that multi-element analysis has potential to be used as a method to trace timber, as this study showed its capability to differentiate concessions on a 100 km scale, based on the heartwood concentrations of several elements. In order to use multi-element analysis as a method to verify the geographic origin of timber, it appears that multiple elements should be considered and especially several transition metals.