August 09, 2022

Growing Trees to Shrink Salt Lake City’s Heat Islands

Written by TreeUtah
View of Salt Lake City's canopy from Capitol Hill View of Salt Lake City's canopy from Capitol Hill Jem Ashton

In the fiery heat of Summer, shade-providing trees are a sought-after resource. They provide us with relief from the heat and they lower overall temperatures in the immediate area. While concrete, roads, and metal absorb and re-emit heat, trees provide substantial relief from the heat by both providing shade and cooling through evapotranspiration. A healthy urban forest is one of our greatest tools in reducing the heat island effect generated by our concrete jungle.

Urban heat islands are caused by a lack of cooling abiotic factors in an environment in addition to abundant human activity. Although minimally perceptible on a small scale, the heat generated by individuals driving, using machinery, or even just jogging builds up, leading to a significant heat increase in the local area. In densely populated urban areas, the heat generated by just living our day-to-day lives with the heat trapped by urban structures accumulates, creating a sweltering heat zone.

Cities overall are much hotter than surrounding rural areas, because of comparably higher levels of human activity and lower square-footage of greenspace. Within cities too, there are areas that have far fewer trees, which leads to even higher temperatures than the rest of the city. This phenomenon is immediately noticeable in Salt Lake City, where shaded areas - like Sugar House or Capitol Hill - feel notably cooler than areas with fewer trees – like Rose Park or Poplar Grove. Although the difference in temperature in these areas might only be a couple degrees, this seemingly small increase in temperature is drastic, especially when the daily temps are reaching the triple digits. With only a 2° increase, energy demands can increase up to 9%, leading to higher energy costs and more pollution.

By growing the urban forest and minimizing these barren, extreme heat zones, we all benefit. We all benefit from lowering temperatures within the cityscape, reducing energy use, and creating welcoming spaces for us all to enjoy year-round. In addition to creating an overall more inviting city for us all to enjoy, we can help protect our neighbors from heat-related illness, keep our waterways clean, and reduce pollution – all by planting more trees. With Salt Lake City’s increased efforts to plant more trees on the West Side and TreeUtah’s partnerships with community organizations in areas in need of more trees, the city’s urban forest will continue to grow and, hopefully, help our community thrive equitably.