PT - JOURNAL ARTICLE AU - C.A. Souch AU - C. Souch TI - The Effect of Trees on Summertime Below Canopy Urban Climates: A Case Study Bloomington, Indiana AID - 10.48044/jauf.1993.049 DP - 1993 Sep 01 TA - Arboriculture & Urban Forestry (AUF) PG - 303--312 VI - 19 IP - 5 4099 - http://auf.isa-arbor.com/content/19/5/303.short 4100 - http://auf.isa-arbor.com/content/19/5/303.full SO - JOA1993 Sep 01; 19 AB - 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.