Thorns

• Acacias produce sharp spines. The thorns appear in pairs on the plant's foliage and stems. The cats-claw (A. greggii) has sharp spines on the surface of its bark. The spines have a curve to them that is reminiscent of a cat's claws. The sharp spines readily snag and rip the clothing of anyone who gets near the tree. Its ability to snag clothing gained the cats-claw the nickname of wait-a-minute bush.
  
  

Ants

• The thorns of the bullhorn acacias (Acacia cornigera and A. collinsii) harbor ants. The Pseudomyrmex ferruginea ants rush off the bullhorn acacia when the tree is disturbed, and bite any interloper. The bites are quite painful. Ants also reside in the thorns of the whistling thorn of Kenya (Acacia drepanolobium). The biting ants help protect the acacia trees and shrubs from herbivores. The ants also eliminate the seedlings of other plants that spring up around the acacia.
  
  

Wood

• The wood of the acacia is highly coveted, but the goat-mouth larvae enjoy hollowing out the acacia wood. The damage caused can render the tree's wood exceptionally weak and unusable. Some acacia trees twist as they grow and age. The twisting makes the wood less than desirable. If the wood of the acacia sustains damage, it will exude a thick, milky substance that helps seal the wound and prevent fungal infections.
  
  

Invasive

• Acacias produce a large amount of viable seeds. The seeds easily germinate and form seedlings. Left unchecked, acacia trees can become extremely invasive. The plant's rapid growth can threaten areas where livestock graze. Most livestock will not graze on the acacia because of its excessive thorns and ant populations. Elimination of the acacia is often difficult. It easily competes with other plant species and overtakes the region.