By applying methods of dendrochronology we separated the influence of the factors limiting the growth, having direct reference to climatic factors. According to forecasts made on the basis of different models a strong global warming for the near future was determined. Quercus robur L. presents a high economic importance in the Romanian forest, therefore the below study is to make a sensitivity analysis to action of oak to “climate as limiting factor”. The obtained result was used for the reconstruction of a climatic parameter called the standardized precipitation index combined for three months (SPI 3). The analysis shows a high sensitivity achieved in the previous year's rainfall formation of growth rings (September and October) and early season rainfall associated to the current growing season (May, June). The importance of this study resides in the need to know by further analysis how this species adapts itself to these climate changes knowing that the species within the area are threatened by extinction if it fails to adapt.