MAKING CITIES MORE LIVABLE WITH TREES
Cities and urban areas are unique ecosystems to themselves. An obstacle to making cities sustainable with shade trees is inappropriate planting details resulting in short-lived trees in urban conditions. The average length of survival of a new street tree in New York City is 10-12 years. Progress has been made through the years but the short life span means that trees do not grow large enough to provide benefits through the shade, habitat, nor reduce and slow rain run-off, nor clean the air. Yet ineffectual installation techniques persist. Arnold Associates' method of planting urban trees is the singly reliable, truly sustainable way proven to date to establish long-lived healthy city trees. The examples shown above explore some of the special installation procedures and the results ten or more years later. This methodology was developed over 40 years ago utilizing a unique structural planting soil we call air entrained soil, and has been successfully employed on many projects since that time. The air entrained soil also lends itself as a lightweight planting soil for intensive green roof projects.