Solutions for Trees: Sidewalks: March 2008 Archives

Sidewalks: March 2008 Archives

City heat island from greenhouse gas and global climate change

The City of Los Angeles has the country's largest roadway and sidewalk system with 6,500 miles of streets and approximately 10,000 miles of sidewalks. And Los Angeles also has the largest urban forest with a population of nearly 700,000 street trees.

A successful sidewalk program includes tree planting. Trees shade sidewalks and the adjacent streets to reduce heat.  Urban areas can be as much as 10 degrees warmer than surrounding open areas, so every tree -- especially MATURE tree counts.

The overall goals of the program are to:

  1. Provide safer and more accessible transit surfaces for pedestrians.
  2. Improve street drainage.
  3. Maintain a healthy, safe, and sustainable urban forest.

Los Angeles, CA has a longstanding policy of replacing every tree removed from sidewalk areas with a minimum 2 to 1 replacement ratio. The Bureau of Street Services uses every sidewalk retrofitting opportunity to expand the  future tree canopy coverage by planting every available site within the sidewalk repair area. Where there is no room to replant trees, vacant planting locations are identified on adjacent streets to plant more than the 2 to 1 replacement ratio.

In the City of Los Angeles, replacement street trees must be 15-gallon size containers or larger. Using larger trees minimizes the occurrences of vandalism and gives the trees a much better chance of surviving.

All trees are planted using root deflection devices, which will help reduce future sidewalk damage. However, the most critical decision for reducing future infrastructure damage is proper species selection.


A municipal arborist is invaluable in selecting species that are compatible with each site. Consider hiring an arborist that is knowledgeable with the trees in your area.


Subscribe in a reader