On Monday, April 22, Earth Day, at 7:30 p.m., the library will welcome Mary Lardie Gaylord who will speak about her recent discoveries at the WHOI NOSAMS Lab, analyzing a historic beech tree for radiocarbon. In April 2015 a huge and ailing European Beech tree planted almost 150 years earlier by Woods Hole’s Joseph Story Fay was cut down and removed from what is now Challenger Drive, on the WHOI village campus. A section of the tree was brought to the NOSAMS facility at WHOI where its radiocarbon content was analyzed. A radiocarbon signal from nuclear weapon testing performed in the 1950s and 60s on the other side of the world, was recorded in this tree and found by the researchers at WHOI. They developed new techniques as they worked on this tree, enabling graduate students to participate in global carbon research.