Studying An Aspen In Colorado (IMAGE) Carnegie Institution for Science Caption Lee Anderegg examining a trembling aspen tree (Populus tremuloides) in the La Plata Mountains of Colorado. Credit Photo is courtesy of Mike Anderegg. Usage Restrictions With credit 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.