Collecting ash tree samples (IMAGE) Penn State Caption Samples for the study were collected by researchers from Penn State, the Forest Service and other partners around the Oregon ash range, extending from California, Oregon and Washington into British Columbia. Credit Penn State Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND 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.