TY - JOUR T1 - The Effect of Trees on Summertime Below Canopy Urban Climates: A Case Study Bloomington, Indiana JF - Arboriculture & Urban Forestry (AUF) JO - JOA SP - 303 LP - 312 DO - 10.48044/jauf.1993.049 VL - 19 IS - 5 AU - C.A. Souch AU - C. Souch Y1 - 1993/09/01 UR - http://auf.isa-arbor.com/content/19/5/303.abstract N2 - The objective of this study is to quantify the effects of trees in a Midwest urban area on air temperature and humidity to determine if the effects are significantly different for: different species of trees, trees of the same species in different environments, and whether the effects can be explained by physical characteristics of the individual trees. Replicate trees in each of five categories were studied: sugar maple, pin oak and walnut individuals overgrass, sugar maple individuals along streets over concrete, and sugar maple clumps over grass. All the trees show a consistent effect: temperatures are reduced and humidities are elevated under the canopies. The greatest cooling effect (0.7 - 1.3°C) occurs in the early afternoon. The difference between species is insignificant, but street trees are significantly less effective in reducing temperature than either individual trees or clumps planted over grass. The clumps had no greater effect than the individual trees. The amount of cooling observed in this study was considerably less than that documented in many previous studies. No consistent linear relationships were determined between physical characteristics of the trees, such as leaf area index, and temperature reductions or humidity increases. ER -