Alonzo_et_al_2021

Alonzo M, Baker ME, Gao Y, Shandas V (2021) Spatial configuration and time of day impacts the magnitude of urban tree canopy cooling. Environ Res Lett. https://doi.org/10.1088/1748-9326/ac12f2

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Keywords: Urban heat island, temperature mitigation, canopy cover

Relationship between tree canopy and cooling is most likely non-linear, with no benefits experienced until 25-50% cover. Clustering of vegetation is a determinant of how much cooling occurs at the site of examination and surrounding areas. Street trees have a “distributed canopy” that is overtop a hard surface – which makes cooling harder. Used impervious surface, building height, and skyview as built factors. Building shade and canopy cover attributed cooling effects. Impervious surface caused similar amounts of heating. Nighttime was crucial because impervious surfaces re-released heat. Soft canopy cover cooled best, hard canopy cover still cooled but was not found at high % and thus cooled less but was still important in the afternoon. Cooling effect changes in evening because trees provide more shade at the decreased angle of the sun. Impervious surface did not have much of an effect because the areas with highest amount of impervious surface also had tall buildings, which provided cooling through shading.