I am examining the relationship between extreme drought conditions and dieback of blue oak (Quercus douglasii) throughout its distribution in CA. My work seeks to identify climatic thresholds that increase the likelihood of dieback occurring in a given area through species distribution modeling. Most of California is expected to become drier in the future – the 2015 drought may be a preview of future vulnerability of blue oak, particularly in the xeric portions of its distribution, or where future climate exceeds the thresholds identified in our model. Our preliminary results suggest that long periods of elevated temperature followed by a reduction in precipitation are hazardous to blue oak survival.