Tree rings tell story of drought

Tree-ring data spanning roughly 1,000 years show that California’s Sacramento River Basin has experienced frequent droughts, some of which lasted for decades. Using the width of annual tree rings to calculate basin stream flow for water years (Oct. 1-Sept. 30), researchers found that 1580 was the driest in the reconstructed record. In comparison, 1977 was the driest in the measured record, which began in 1906. Return to story