Treeline (IMAGE) Columbia Climate School Caption Tree ring researchers Edward Cook (left) and Paul Krusic trekked for nearly two weeks to reach this 1,000-year-old hemlock in Nepal. Credit Brendan Buckley/Lamont-Doherty Earth Observatory 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.