Design Suitability as the Lesson: Comparison of Research Designs and Mixed-Methods Appraisal in Urban Forestry Teaching Beyond the Classroom

Abstract Research design is a foundational competence in environmental science education, yet its implications are rarely experienced firsthand before graduate research begins. This paper reports a three-part field exercise conducted with Forestry postgraduate students at Manipur University, India, in which the methodological lesson emerged from students’ own data rather than from the classroom’s lecture-based instruction. Students first collected beneath-canopy air-quality data under a Completely Randomized Design (CRD) for five canopy categories, including a control (n = 25) and, independently, under a spatially structured campus-quadrant design (n = 60). Because tree-species composition differed across quadrants, the second design did not meet the completeness condition of a true Randomized Block Design (RBD); we treat this shortfall as the central teaching artifact rather than a defect to be hidden. Under the CRD, five of eight air-quality parameters showed large canopy-related effects (partial η² = 0.48–0.75); once spatial block was accounted for, most of these effects weakened substantially, with block itself becoming the significant source of variance for particulate matter. A second exercise asked 25 students from 25 departments to complete a short perception survey; 88% reported that campus greenery positively influenced their academic life, a dimension that the biophysical measurements could not capture. A third exercise required students to compare all findings and to judge, rather than assume, what each design could and could not support. We describe the exercises, the assessment rubric used, and the broader case for teaching design suitability as an explicit, examinable skill in biology and environmental-science curricula.