When buildings or homes are built in our cities and towns, the natural layout and structure of soils is heavily modified, and often changed in erratic ways. Large holes are dug, bringing soil horizons meant for the deep areas, to the surface; mixing heavily with surface horizons. The top O and A soil horizons are often scraped clean to level surfaces, moving them or completely taking them away. Outside products, like “clean-fill” are often brought in, adding foreign soil or even rock (like quarry, limestone fill) into the surface soil area.

On top of this sub-par growing medium we’ve created, we also plant turf or put asphalt and concrete into most of the area. We then rake up and get rid of all organic litter and material, continually robbing the soil of the reincorporation of organic matter that forests are accustomed to. To add to the problem, urban trees are grown quickly using synthetic fertilizers on tree farms, and then dug up to be planted, cutting anywhere between 50-90% of their roots off, and often planted in different soil than they were grown in.

This entire predicament creates poor chemical, physical, and biological soil characteristics, resulting in poor urban tree growth, increased insect and disease populations, and high rates of nutrient deficiencies. (Read more)