The Ecology of Tree Roots and the Practical Significance Thereof

Abstract

Tree root growth is opportunistic and occurs wherever the environment is favorable. A balance exists between the root system and the remainder of the plant, so that if part of the root system dies, part of the crown will also die. Both parts are connected by a well-developed conduction system. Approximately 99 percent of the roots occur within the surface meter of soil and extend outward over an area one to two or more times the height of the tree. Large woody roots form the framework and are typical in pattern for each species. The fine feeder roots occur in the leaf and litter layer, if present, and the surface mineral soil. Keen root competition occurs at the surface if a turf exists under the tree. Also, herbicides, etc. used on lawns may have detrimental effects on the trees through these fine absorbing roots. In the urban environment roots may follow cracks and crevices in pavements, pipelines, sewers and cables. At the same time the installation of these utilities may cut across established tree root systems with unfortunate consequences.