We study the origin and provenance of instream wood using stable isotope ratios (D/H and 18O/16O) that depend on the water source (e.g., rainfall, river flow, glacier), and persist in the cellulose once it is absorbed by the tree. Once a tree falls in a river, the water in the cellulose could be altered as a result of an exchange with the river water; however, the effect of this exchange in the isotopic composition of the water cellulose is unknown. To observe whether the isotopic signal in wood cellulose changes, we placed sample specimens from living trees in the Sorge-Chamberonne stream under three different conditions, i.e., emerged on the floodplain, partially and totally submerged in the water. Specimens will be sampled and the stable isotope ratios (D/H and 18O/16O) in the wood cellulose will be analysed with a Mass Spectrometer every three months during at least the next three years.
This work is part of a PhD thesis. To know more about this experiment, you can contact Javier del Hoyo.