The acacia tree is well adapted to xeric conditions and is often found in dry arid lands. It has evolved an extensive root system that allows it to get the most out of the available water. It has a widespread root system lying close to the surface, that takes up water from the rare precipitation.

In addition, the acacia tree has long tap roots that can reach all the way down to the permanent water reservoirs buried deep beneath the surface. As a result, the acacia tree has access to water at all times which keeps the tree alive during droughts.

In xeric habitats, animals get most of their water from eating plant material or insects, hence the acacia tree has evolved spines close to their leaves to keep animals away. As a second line of defense, the leaves are filled with distasteful chemicals. An example of an acacia tree is shown in the image below.

Figure 1. Acacia tree

Otieno, Dennis Ochuodho,et al. (2005).生理和形态对水的反应stress in two Acacia species from contrasting habitats. Tree physiology,25.3 (2005): 361-371.