Core Sample from Hecate Island Tree (IMAGE) University of Oregon Caption Trees are like big thermometers, says Kira Hoffman, a doctoral student at the University of Victoria. Here she extracts a core sample from a western red cedar tree as part of her effort to understand historic climate variability in the northern reaches of the Pacific Northwest. Credit Photo by Malcolm Johnson Usage Restrictions Use photo 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.