Street Trees Reduce Night Heat and Improve Shade Comfort

Street trees in Las Vegas reduce nighttime air temperature by up to 1.5°C but have minimal daytime cooling due to stomatal closure and increased sensible heat flux.

Using a high-transpiration species triples evaporative cooling and achieves about 0.4°C daytime temperature reduction at the cost of three times more water use.

Tree shade intercepts solar radiation, lowering mean radiant temperature by up to 16°C and greatly improving pedestrian thermal comfort.

Cooling effectiveness varies with tree species, cover fraction, and placement in the urban canyon, highlighting the need for site-specific evaluation.