By Rachel Roberts
Almost 80% of the United States’ population lives in urban areas dependent on the many benefits provided by urban trees and forests.
Typically, the term “urban forests” refers to the publically and privately owned trees within an urban area, including in backyards and along streets. Recently, however, the term “urban forests” has been used to reference the plans developed by an increasing number of U.S. cities to preserve their trees. Cities with comprehensive urban forest plans include New York, Philadelphia, and Portland, among many others.
Aside from their aesthetic appeal, trees can benefit urban populations in a number of ways, including reducing summer peak temperatures, preventing storm water runoff, noise abatement, improved water quality, diverse wildlife habitat, and increased human-health and well-being.
For example, Philadelphia’s Clean Waters Program is focused on restoring the city’s watershed with trees to help intercept, filter, and store storm water to help alleviate some of the load for the city’s drains and pipes.
Similarly, in Portland, urban forests are what the city refers to as “green infrastructure.” On average, a single tree has the potential to intercept more than 500 gallons of storm water per year. The water is absorbed by the tree’s roots or caught in the canopy and evaporates before it hits the ground. This reduces the amount of water that flows through the city’s municipal drains and pipes by more than one billion gallons annually.
It is estimated that urban forests in the United States contain 3.8 billion trees, with a structural asset value estimated to be $2.4 trillion. This only reflects a portion of the total net worth of an urban forest, though, as ecosystem services and benefits to both physical and social environments, such as increased air quality or community well-being, are usually not accounted for.
Although taken for granted, the benefits trees provide to both society and the environment that are irreplaceable. Numerous studies have shown that neighborhoods with more trees tend to have higher property values, better neighborhood interaction, and lower crime rates in addition to the ecosystem services mentioned above.
Trees provide services to the earth that are beyond quantification, so take a moment to appreciate all that urban trees do for the environment and us city dwellers.