In natural landscapes and forests - dominated by large trees and lush vegetation - growth seems unstoppable. Here in nature, soils are dominated by dense networks of beneficial mycorrhizae fungi.
In urban soils, however, there are only very low levels of this beneficial fungi.
This is mainly due to the way the urban soils have been damaged. During the construction of homes, roads, plazas etc., much of the natural topsoil is removed and carted off-site, exposing the nutrient deficient, low organic content subsoil. The remaining topsoil is left in piles to bake and decay while the construction is completed. Heavy machinery pulverizes and compresses the ground even further, and once construction is finished, the pile of dedicated topsoil is spread in a thin layer over the subsoil before planting begins.