AMHERST, Mass. - Can plants affect our moods? John Tristan, director of the Durfee Conservatory at the University of Massachusetts and a certified horticultural therapist, believes they can. With the help of the UMass School of Nursing, the UMass Statistical Consulting Center (SCC), and several honors students enrolled in the horticulture program, Tristan has launched an extensive research project he hopes will establish, once and for all, the role living plants might play in helping people reduce their stress levels.