The tree line is the edge of a habitat at which trees are capable of growing. In this study, the scientists wanted to examine dead trees that they found above the current tree line. The deadwood found above the current tree line indicated that the climate during the trees’ lifetime was different than it is now. The scientists were interested in learning about the climate that existed when these trees were alive. Topics: Active Forest Management, Dendrochronology, Global Positioning System, Preservation, Volcano.