Benefits of Urban Greening

It’s obvious that street trees and sidewalk gardens beautify our urban environment.  They provide so many other benefits that the U.S. Environmental Protection Agency and city planners regard them as part of a city’s “green infrastructure.”

Yet more than half the available street tree sites in San Francisco are currently unplanted.  We must plant more trees and sidewalk gardens to take full advantage of the benefits available to us, such as:

Trees increase property values

Dollar sign hanging from tree

  • Street trees increase the “curb appeal” of properties.  A study of the sale of houses in Portland, Oregon found that on average, street trees add 3% to the median sale price of a house and reduce its time-on-market by 1.7 days.

Trees produce oxygen, clean the air and reduce global warming

Drawing of tree that looks like lungs

  • Trees release oxygen as a product of photosynthesis.  Two medium-sized, healthy trees can supply the oxygen required for a single person for a year. (see source)
  • Trees clean the air by absorbing greenhouse gases that contribute to global warming; they store carbon dioxide, the primary greenhouse gas, in their stems and leaves. (see source)
  • Trees capture airborne particles such as dirt, dust and soot; a mature tree can absorb 120-240 lbs of particulate pollution each year, (see source)
  • A 2008 study by researchers at Columbia University found that more trees in urban neighborhoods correlate with a lower incidence of asthma.

Trees and sidewalk gardens reduce flooding and water pollution

House floating away in flood

  • During rainstorms, water can overload our combined storm-sewer system, resulting in polluted runoff into the San Francisco Bay.  This runoff contains chemicals washed from our streets by the rain.  Trees reduce this problem by capturing rain; a mature tree can store 50 to 100 gallons of water during large storms, and the concrete removed from our sidewalks for street trees and sidewalk gardens allows rain to soak into the soil. (see source)
  • The average San Francisco street tree intercepts 1,006 gallons of rainwater a year. (see source)
  • The interception of stormwater by San Francisco’s entire urban forest has an annual value to the city of $467,000. (see source)

Trees calm traffic

  • The presence of trees reduces the speed of drivers, and reduces the frequency and severity of crashes. (see source)

Trees and sidewalk gardens increase revenues in shopping districts

  • Consumers have a 12% higher willingness to pay for goods and services in retail areas that have streetscape greening such as street trees and sidewalk gardens. (see source)

Trees and sidewalk gardens may reduce crime

  • The greener a building’s surroundings, the fewer reported crimes.  Apartment buildings with high levels of greenery had 52% fewer crimes than those without any trees.  “Green” spaces are used more frequently (by pedestrians and for recreation), which increases “eyes on the street” and deters would-be criminals. Residents living in “greener” surroundings report lower levels of fear, fewer incivilities, and less violent behavior, because greenery promotes a greater sense of community and alleviates mental fatigue, a precursor to violent behavior. (see source)
Tree-lined sidewalk

Tree-lined sidewalk on Eddy Street in the Western Addition

Trees and sidewalk gardens promote exercise

  • In a neighborhood with more street trees and other plants, people judge walking distances to be less, and are therefore more likely to travel on foot, which has health benefits. (see source)

And more benefits…

  • Trees make the wait for a bus feel shorter. The more mature trees are present, the shorter the wait time is perceived. (see source)
  • Street trees and sidewalk gardens create a physical and mental barrier between the street and the sidewalk, keeping pedestrians, children and pets out of harm’s way.
  • Street trees and sidewalk gardens provide a natural habitat for birds and insects.
  • Street trees absorb traffic noise and increase privacy.
  • Street trees and sidewalk gardens build neighborhood and civic pride.
  • Neighborhood planting events strengthen communities and bring neighbors together.

Smiley face with trees on itBenefits of working with Friends of the Urban Forest

  • Thanks to more than three decades of experience, we’re expert in the selection, planting and care of street trees and sidewalk gardens in every neighborhood in San Francisco.
  • We manage every step in the process, from site inspection to species selection to planting and follow-up care.
  • Our group planting events bring neighbors together to transform their block.

Let us help you get a street tree or sidewalk garden!