We would not expect a palm tree to grow in Chicago, or an upland oak tree to grow in a swamp. Urban environments, especially below ground, can be just as foreign to any tree and must be managed to provide the basic requirements needed for good root growth.
Trees planted in the built environment must cope with conditions much different than where they evolved in nature, above and below ground. Up to 80% of urban tree problems originate below ground and threaten sustainability of the urban forest. The half of the tree below ground is challenging to study, and is often overlooked. This long-standing Morton Arboretum program has been a major contributor to what we know about the urban Landscape Below Ground. Current research is focused on how root systems of trees planted in built environments are impacted by the nursery production, planting procedures, and by disturbances throughout their life-span. Severing woody roots, and subsequent root regeneration alters root system architecture. Replacement of roots lost can take years, during which time trees can be severely stressed. Once developed, the altered root structure may be less stable, and poorly suited for survival in poor quality urban soils. Understanding how these affect tree health and stability is important for tree longevity and sustainability.
The Morton Arboretum, J. Frank Schmidt Family Charitable Foundation