How far do tree roots typically spread?
Written by
Julia Anderson
Reviewed by
Prof. Charles Hartman, Ph.D.The spread of tree roots varies considerably depending on the type of tree and its environmental conditions. In the natural forest, the roots extend several times the width of the crown in their search for food. The roots of trees planted in cities extend shallowly and widely in the fight against restrictions. The two factors, volume of soil available and the possibility of water, are important.
Environmental Constraints
- Soil volume determines maximum expansion capacity
- Physical barriers like foundations redirect growth patterns
- Water sources attract roots toward moisture zones
Biological Factors
- Species genetics program inherent spread tendencies
- Competition density from nearby plants limits resources
- Mycorrhizal networks extend nutrient reach
The available volume of soil has a large effect on the width of root growth. In forests, trees have access to hundreds of cubic meters of soil. In urban settings, trees often must grow in tree pits covered by pavement. This forces root systems to spread out more and search for nutrients. In urban areas, root systems tend to be extensive and shallow. They then suffer when pavement occurs above them. Sidewalks are lifted when there are no longer places for the roots to spread.
Diverse sources of water for direct root explorations. Roots have the innate ability to sense changes in soil moisture. They then pursue the direct line to an uninterrupted water supply. This explains why trees are unmesehed near streams, as they grow with a species of unbalanced roots. In dry tracts of country, the distribution is more extended, to secure a limited supply of moisture. Irrigation systems exercise a similar influence upon the plants.
Physical barriers completely change root architecture. Foundations cause roots to grow parallel along structures. Pavements cause 90-degree changes in root paths. Trees near buildings create unbalanced systems. These changes make trees less stable in high winds. They also pose a high risk of failure.
The genetics of the species provide the basis for the spread of various behavioral types. Willows develop large mats in search of water. Oaks produce a deep and more compact system. Pine roots extend far in a sandy soil. Knowledge of these facts provides insight into the developing success of planting. It prevents conflicts with the the military system before it is developed.
Read the full article: 7 Essential Facts About Tree Root Systems
