Roots in sandy soils will be more extensive, less fibrous and fewer in number. Root to Shoot Ratio For trees to function at their optimum, as the above ground portion of the tree grows and expands, so must the root system. The relative relationship of the root to the shoot is expressed as the ration of the weight of the root to the weight of the top. Another way to view the root system is to consider that a seedling may have 2 to 6 feet of root length while the root system of a mature oak tree may be hundreds of miles in length. Roots have no regular branching pattern like the shoots which develop at nodes from buds in the axils of leaves.
Lateral roots arise from tissue on the outside of larger roots.
The root cap protects each root tip as it is forced through the soil by elongating tissue just behind the tip of the root. Just back from the root tip are the root hairs which are fine outgrowths of single cells. Water and nutrients are absorbed through root hairs and by the tips of these smallest roots. Root hairs are functional for a few weeks to two years and then are sloughed off. Most tree species are infected with mycorrhizae.