By how many degrees can trees lower the Urban Heat Index?

Trees play a significant role in mitigating the Urban Heat Index through their shade, evapotranspiration, and overall cooling effect on their surroundings. The correct range of 4-10 degrees reflects the real-world impact that a well-planned urban tree canopy can have on temperatures in city environments.

The cooling effect of trees varies based on several factors, including the species of tree, its size, and the density of the canopy. As trees grow, they transpire water through their leaves, which cools the air around them. Furthermore, shaded areas under trees experience less solar radiation, leading to lower surface and ambient temperatures. Studies have shown that areas with adequate tree cover can experience a noticeable drop in temperature, contributing to enhanced comfort for residents and reduced energy consumption for cooling.

The other ranges provided do not accurately represent typical findings from urban forestry studies. While larger, mature trees and dense groves can contribute to greater cooling effects in specific scenarios, the average urban tree cover generally achieves a reduction within the established 4-10 degrees range. This range is practical and supported by scientific data regarding urban microclimates.