The Swiss Federal Institute for Forest Snow and Landscape Research WSL

Isotopes tell the tree crown’s story

In each individual tree ring of a wood sample, we measure light and heavy atoms, i.e., the "stable isotopes" of the chemical elements carbon (C) and oxygen (O).

Their proportions provide key information, for example, on how trees have regulated CO2 uptake and water evaporation (transpiration) through the stomata of their leaves and needles under past climatic conditions.