At the Catamount Center outside Woodland Park, Colorado, Nicolai Calabria ’18 leads students from Columbine Elementary School in an experiment to sample lake water, looking at macroinvertebrate life as one indicator of the lake’s health. Calabria is participating in the TREE Semester at CC. TREE stands for Teaching and Research in Environmental Education and is a 16-week, residential semester program where undergraduate students live and learn in community at Catamount, mirroring the traditional study-abroad experience.