Williams extracts a core from a massive red oak. Specimens up to 400 years old can be found in isolated spots, but it is the last 80-some years the scientists are mainly after

AGU25, the premier Earth and space science conference, takes place December 15-19, 2025 in New Orleans, Louisiana. This year’s theme—Where Science Connects Us—puts in focus how science depends on connection, from the lab to the field to the ballot box. Once again, Lamont-Doherty Earth Observatory and Columbia Climate School scientists, experts, students, and educators are playing an active role, sharing our research and helping shape the future of our planet. #AGU25 Learn More