Native Plant Conservation Campaign News: Poor city neighborhoods have fewer trees, higher heat stress than wealthy areas.

September 11, 2019

 

A U.S. Forest Service report found that from 2009 to 2014, 44 states lost tree cover in urban areas. Approximately 28.5 million trees were lost every year to development, disease, invasive species and severe storms.

 

Last week, a National Public Radio analysis found that low-income areas in dozens of major U.S. cities tend to be hotter than wealthier neighborhoods, and they are disproportionately communities of color. Lack of tree cover is a major contributing factor. For example, in Louisville, KY, wealthier areas have up to twice as many trees as do poorer areas.

 

Research consistently shows that, among many benefits to human health and well-being, tree canopy and green spaces substantially reduce urban heat. Through transpiration alone a single tree can cool its surroundings as effectively as several air conditioners. Shade of course further cools areas under tree canopy.

 

The NPR story contains maps of urban heat islands and the spatial distribution of income in U.S. cities, confirming the prevalence of higher temperatures in poorer neighborhoods.

 

The story also reports on efforts to address this problem, including the Green Heart Project. Green Heart plants fully grown trees, as tall as 30 feet, in a test area within Louisville. The five-year study will measure the effects on health indicators, particularly those for heart health, of the plantings. The hope is to use the data to persuade other cities to invest in tree planting.

 

In addition to improving health, trees also fight climate change and improve air quality by absorbing carbon dioxide and other air pollutants, among many other benefits. In fact, the Forest Service study estimated with the loss of trees, cities lost air purification, carbon sequestration, and other ecosystem services valued at $96 million per year, conservatively.