DAMAGED ROOTS - Tree decline may be the result of severed or damaged tree roots. If roots are severed, some buds and twigs may immediately die, weakening the tree. The weakened tree may begin to show decline symptoms such as lack of vigor and reduced growth. Other stress symptoms can include wilt, scorch, and early fall color (also signs of drought). In addition, trees with severed roots may lean or show symptoms on the side of the tree with root damage. These symptoms usually progress over a number of years.  Trees may survive and recover if the damage does not exceed 1/4 of the total root zone. Roots may be severed during nearby construction and excavation, especially for streets, sidewalks, footings, foundations and walls. Trenching for utilities may also sever tree roots.  Also, steam pipes can change the climate of the soil resulting in root death.  It is advisable to tunnel under tree roots larger than 2".  Other strategies to avoid damage include, use of paving materials which require a minimum amount of excavation, locating the construction of structures away from mature trees, and avoiding the stripping of topsoil around trees. When clearing land, cut woody vegetation to ground level rather than pulling out large root systems, which may damage nearby tree roots.
    At Morris Arboretum, several of the Shumard oaks in the Oak Allee were planted too deeply in the ground and are now doing poorly.  Planting the roots of a young tree with too much soil piled over them can cause the roots to become suffocated.  The thin, fibrous roots of a young tree are the main source through which the tree draws water and nutrients.  If these roots are covered with too much heavy soil, the roots will be suffocated and be rendered useless.
To help maintain healthy roots or to try and minimze the effect of damage roots water during periods of drought. Prune out any branches that die as a result of the reduced root system.  If more than 1/4 of the root system is affected, have a hazard tree inspection done by a certified arborist to determine safety issues.  Remove the tree if it is necessary.