Core Sample (IMAGE) The University of Montana Caption Kyra Wolf, a University of Montana Ph.D. candidate, holds a sample of charcoal and other organic materials from a core from a lake in western Montana. Variation in charcoal within the core is used to reconstruct past wildfires. Credit UM photo 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.