Bristlecone (IMAGE) University of Hawaii at Manoa Caption Bristlecone trees, such as this over a thousand-year-old tree in the Great Basin National Park, contributed to the tree-ring record on El Niño. Credit Image courtesy International Pacific Research Center 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.