Street trees and sidewalk gardens do much more than beautify our urban environment. The many different benefits they provide justify our regarding them as part of the city's "green infrastructure" - to be nurtured and protected.

Benefits of urban greening
Two medium-sized, healthy trees can supply the oxygen required for a single person for a year.

Producing oxygen, cleaning the air, reducing global warming

  • 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.
  • 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.
  • Trees capture airborne particles such as dirt and dust

Reducing flooding and water pollution

  • During rainstorms, water can overload the combined storm-sewer system, resulting in polluted runoff. This runoff contains chemicals washed from the 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.
Joburg City Parks and Zoo's ongoing maintenance programme
Joburg City Parks and Zoo's ongoing maintenance programme covers over 7 500 hectares, of which almost 2 000 hectares are road islands and public space on either side of the city's main and arterial roads.

Increasing revenue in shopping districts

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

Promoting 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.

Other benefits

  • 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 neighbourhood and civic pride.
  • Neighbourhood planting events strengthen communities and bring neighbours together.

REFERENCES

1. E. G. McPherson, J. R. Simpson, P. J. Peper, A. M.N. Crowell, and Q. Xiao, 2010, Tree guide:  Benefits, cost and strategic planting, Northern California Coast Community

2. http://www.fuf.net/benefits-of-urban-greening/