Deer Ridge, Rocky Mountain National Park (IMAGE) University of Colorado at Boulder Caption Increasing tree die-offs in the West are illustrated by these gray, needleless limber pine, the likely victims of drought, interspersed with orange, dead limber and ponderosa pine killed by Rocky Mountain pine beetles in Colorado's Rocky Mountain National Park in recent years. Credit Image courtesy Jeremy Smith, University of Colorado 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.