Predominant drought cycles in the Intermountain West

The Intermountain West belongs to a unique climate regime that is not controlled by any of the prominent climate modes like El Niño. Climate records from both instruments and paleochronology indicated repetitive drought cycles spanning about 10-15 years. The lack of understanding in what causes such drought cycles hampers current prediction capability for climate models. More research thus is needed to explore this climate oscillation. As part of the U.S. Forest Service’s Forest Inventory and Analysis (FIA) comprehensive forest survey, tens of thousands of tree cores were sampled on an approximate 5 km grid. Many of these cores span several centuries and represent all forest types. Hence, the core strength of the FIA tree-ring data is the unprecedented resource of a long-term documentation of climate variability coupled with high spatial resolution for reconstructed variables for mountain regions where data have been previously unavailable