Widespread Tree Die-off in Sierra Nevadas (IMAGE) University of California - Irvine Caption A massive tree die-off struck California's Sierra Nevada mountain range at the end of the 2012-2015 drought. Numerous stands, such as the one near Soaproot Saddle (pictured), suffered significant losses caused by the exhaustion of soil water supplies tapped by the trees' deep roots, a recent UCI, UC Merced study concluded. Credit Margot Wholey / UC Merced Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.