Trees line the streets in a county island within the city limits of Fresno, California. There are no sidewalks in these neighborhoods. However, what the residents gain in benefits beats the convenience of a sidewalk.
Urban Trees Reduce Energy Use and Electricity Bills
Urban trees decrease energy use in cities like Fresno. They reduce energy use by cooling air temperatures and changing wind speeds around buildings. Fresno is a city where summer temperatures regularly soar past 100 degrees F. Shade is always welcome.
Trees and forests in urban areas across the lower 48 states reduce electricity use by 38.8 million megawatt-hours ($4.7 billion). They also decrease heating use by 246 million MMBtu ($3.1 billion) and prevent thousands of tons of emissions of several air pollutants annually.
Reducing energy use also reduces electricity bills. Planting trees on the south and west sides of houses in Sacramento, California, reduced electricity bills in the summer by $25.16 on average, researchers discovered. California has some of the highest electricity bills in the nation, and the Central Valley cities of Fresno and Sacramento are no exceptions.
A separate study by the same researchers, in Portland, Oregon, found that planting a tree in the front yard or near the house added $8,870 to a home’s sale price and reduced the time on the market by almost two days. One tree also added a combined value of $12,828 to all houses within a 100-foot radius.
Planting Trees Decreases Carbon Emissions
Trees absorb carbon. Just one mature tree will absorb over 48 pounds of carbon dioxide from the atmosphere in one year. An analysis for Baton Rouge, Sacramento, and Salt Lake City found that planting four shade trees per house would reduce power plant carbon emissions by 16,000, 41,000, and 9000 tons, respectively.
When cooling is factored in, the savings increase by at least 25 percent. The Heat Island Group at Berkeley Lab found that a tree planted in Los Angeles prevents the combustion of 18 kg of carbon a year, making that one tree equivalent to three to five forest trees.
Trees Improve Mental and Physical Health
“Just living is not enough… one must have sunshine, freedom, and a little flower.” Hans Christian Andersen
Being around trees gives mental health benefits, including less stress and improved thinking. Peter James, an assistant professor in Harvard T.H. Chan School of Public Health’s Department of Environmental Health, said that spending time amongst trees can “translate into long-term changes in the incidence of depression, anxiety, cognitive decline, and chronic diseases, including cardiovascular disease and cancer.”
The U.S. Needs More Urban Parks
As climate extremes become more common, these benefits are increasingly important. Last year was the fourth-warmest year on record in the contiguous U.S. Most Americans (80 percent) live in urban areas. One young, healthy tree provides the equivalent cooling of 10 room-size air conditioners working 20 hours a day. Research on three cities (Portland, Oregon; Sacramento; and Chicago) found that trees improved air quality, lowered electricity bills, and increased home values.
There are over 1 million acres of urban parks in the U.S., and Central Park in New York City is one of the nation’s most famous. There are more than 18,000 trees in the iconic park, which remove around one million pounds of carbon dioxide from the atmosphere every year.
Given these examples, the potential impact of city-scale tree planting becomes clear. What if every major U.S. city had its own version of Central Park? How much energy and carbon dioxide would the trees living in those parks reduce? How much happier and healthier would residents become?
Let’s play a little more of the “what if” game. Imagine more urban areas with tree-lined streets like those of county islands in Fresno.
