The stable isotope ratio of Carbon and/or Oxygen (δ¹³C resp. δ¹⁸O, d) in whole wood and incellulose is directly linked to environmental factors as well as to the physiological response of the trees to these factors – at the time when the organic material was formed. Thus the isotopic signature in tree rings can be used directly as a physiological archive. Physiological isotope investigations combined with molecular biological methods can in future enable efficient and time-saving tests for climatic sensitivity of provenances of a tree species.Within this paper, we present a study of δ¹⁸O and δ¹³C in the late wood of different Douglas fir provenances assessed retrospectively in an altitudinal transect (Oberrheinebene Schwarzwald) by isotope ratio mass spectrometry. Special attention has been payed to the physiological reaction of the provenances in years with extreme atmospheric conditions (e.g. the extreme dry year 2003) and in the following years. Isotope ratio measurements were conducted for treerings formed in the years 2002 until 2007.The results of the isotope ratio measurements showed clear distinctions between different Douglas fir provenances in their physiological reaction to rigorous drought, as observed in 2003. Isotope ratio measurements revealed that some but not all provenances intensively closed the stomata to reduce water consumption as a consequence of the drought in 2003.