Samples from ash trees (IMAGE) Penn State Caption The researchers analyzed genomic variation from more than 1,000 individual trees from 61 separate populations around the Oregon ash range. Some of the samples are shown here. 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.