Beetle-killed ponderosa pines (IMAGE) DOE/Los Alamos National Laboratory Caption Warming temperatures and the 2012-2015 megadrought fueled an outbreak of western pine beetles that decimated forests in the Sierra Nevada. Future conditions may limit both the scale of infestations and regrowth of timber to pre-megadrought levels. Credit Zachary Robbins/Los Alamos National Laboratory Usage Restrictions No restrictions. License Public Domain 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.