Different species colonize different sections of the soil.  The table below shows the rooting depths of a number of important woodland species found in northern Namibia.

Plants that are shallow rooted need to be able to cope with a greater fluctuation of water and temperature around the roots, although Smith & Grant (1986) suggest that the shallow roots enable plants to access rainwater sooner than others.

Similarly, the shallow roots also allow plants to access minerals from the ash of fires.  However, Mitlöhner (1999) suggests that a high fire frequency may change the soil solution, particularly of the upper soil layers by changing the osmotic potential, that plants may later be unable to obtain sufficient water.

The findings of Timberlake & Calvert (1993) show that the rooting strategy may be influenced by soil.  Rooting systems of Terminalia sericea in Kalahari sand extended to lower lying soil layers than in heavier soils.  This is possibly due to the faster infilltration of water to lower soil layers in loose sand.