This “clicker” case uses a handout and a PowerPoint presentation to guide students through the interpretation of three key traits of two dominant boreal species in the high elevation regions of northern New Hampshire to develop hypotheses concerning each species’ shade tolerance. Students are given actual data to assess how these species differ in functional traits and to draw inferences about the species’ relative shade tolerance. Beginning with classical niche theory and advancing to the use of functional traits to define the niche or trait-space of each species, students develop hypotheses about species competition based on niche overlap and how competitive interactions may change with species migrations in the future. Lastly, to emphasize the importance of critical thinking, students consider the limitations of this study based on the study design, identifying problems and generating solutions to expand the applicability of these findings. The case is appropriate for a variety of upper-level undergraduate courses including forest ecology, plant ecology, plant physiology, and ecogeography.