Motivated by interest in Fall 2014 during the National CZO All-Hands meeting at Yosemite National Park, the SSHCZO hosted 30 specialists from across the country and Canada to “Explore Four Critical Puzzles abut Trees, Soil, and Water” during a 2.5 day workshop at Penn State.  The group of scientists discussed the current knowledge of biogeochemistry, ecology, geomorphology, and hydrology with a focus on critical zone mixers, such as trees.  By the third day, discipline specific barriers in thinking and communication were broken and the excitement of emerging testable hypotheses was evident.   Participants will stay engaged of the next few months with the target goal of a vision paper to be submitted.