by Livia Costa
Resting under the cool shade of a tree is one of the simplest, most refreshing joys of summertime. As climate change makes heat waves more common, cooling down has become crucial… especially for those who live in cities.
Cities often experience higher temperatures than suburbs, and this phenomenon has direct ties to the amount of tree cover in an area. The more concrete, asphalt, and impervious surfaces an area has, the higher temperatures are, creating a “heat island.” The risks of these increasing temperatures, in addition to making us sweaty as we wait for the subway, pose dangers to our health. High air temperatures kill more people in the United States than any other weather-related public health threat, and we can expect this to increase in the coming years. This impact is magnified for those without access to air conditioning (AC) units, infants and the elderly, folks without homes, and people with health issues.
Pollution, largely from heavy traffic, also poses a major public health risk in cities. Exposure to air pollutants has been linked to various health consequences such as premature death, lung and heart disease, and asthma, all of which disproportionately affect vulnerable groups. Boston is among the top 20 most challenging places to live with asthma, and children who grow up in urban neighborhoods have higher rates of asthma and an increased vulnerability to serious health risks.
“Urban trees are the key to mitigating these effects and healing both the health of the planet and those who live within it. Trees create more livable cities.”
Urban trees are the key to mitigating these effects and healing both the health of the planet and those who live within it. Trees create more livable cities. They provide crucial ecosystem services such as filtering stormwater runoff, wind suppression, reducing temperatures, filtering the air, and providing homes for wildlife. When it comes to trees reducing temperatures, they are masters. Trees have been known to decrease the average temperature of an area up to 10 degrees, preventing about 1,200 deaths during heat waves. They do this by not only casting shade which instantly cools the area beneath it, but they also serve as natural air conditioners by releasing water vapor, cooling entire blocks (this is called evapotranspiration!). Trees also serve as effective air filters, trapping pollutants in the air and helping to avoid 670,000 incidences of acute respiratory symptoms each year. Trees even improve mental health and have been shown to decrease stress and anxiety, and could even reduce the need for antidepressants among city dwellers.
Trees are an essential infrastructure in our cities. However, in Boston and many major cities around the country, the benefits do not extend to everyone. In fact, wealthier neighborhoods have significantly more tree canopy than other less affluent communities and there is a troubling and very real reason for this. Tune into part two of this blog to learn more about Tree Equity and how different communities in Boston experience disproportionately less tree coverage and why. In the meantime, visit arborday.org to learn more about the power of trees and make sure to get out into nature and experience these wonderful benefits!