Roots are the part of a plant which is usually beneath the ground, and serves as a food store, and mechanical support. Also, minerals and water are being absorbed by the tree through the roots. The shapes of roots vary. Oaks and Pines, when grown in sandy and dry soil, develop so called tap roots. Tap roots are roots which grow directly beneath the trunk. Usually, urban trees do not develop such roots, and they are not common if there is enough water in the ground (Perry 1982). Roots don’t follow a specific growth pattern rather, they grow where there are more minerals or water. Since roots also need oxygen, most of them do not grow very deep. Also, roots do not grow where the soil is very hard as they tend to avoid such areas. The area that the roots occupy is usually bigger than the size of the tree canopy, sometimes it may be as big as the height of the tree, but in many cases it grows 2 or 3 times bigger then the tree’s height in first 3 years of planting (Perry 1982).
In trees such as Oaks, there is a strong connection between the root’s position and its’ leaves. If the roots are injured the tree will drop its’ leaves at the same side where injury took place, while trees such as Maples loose leaves on random branches. The majority of tree roots are situated very close to the ground’s surface, which makes trees vulnerable (Gilman 1991).
A griding root is a common reason for a Maple’s decline. It is a root which grows around the main trunk. As the trunk and the roots grow bigger in diameter, it starts to strangle the trunk. This strangling disturbs the mineral and water flow from the root system to the leaves, and becomes problematic for the tree. It can eventually lead to a tree’s decline, or in some extreme cases, to its’ death. A griding root is not limited to but usually effects human planted trees, and it happens because of the way the seedling was planted. Therefore one should be careful in root positioning when planting a tree (Forest Resources Extension).
Another reason for a tree’s decline is a situation where the roots are visible above the ground. This is caused by erosion. This occurs most commonly when a tree is growing on a hill. Also in soil, which consists of clay based materials, a tree can be prone to erosion. Weather conditions also contribute to exposure of the tree’s roots. Trees with exposed roots are not so resistant to dry out periods which contribute to possible tree decay or death (McAuliffe et al. 2006).
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