Pioneering species
Acacia karroo is a fast growing species that establishes readily in full sunlight and does not need shelter or protection from grass fires. Seed germination might be promoted by fires. Sweet thorn is resistant to heavy grazing, to fire and to frost. Grazing by goats has been suggested for the alleviation of bush encroachment (Dingaan et al., 2018).
Soil improver, erosion control and reclamation
A N-fixing tree, Acacia karroo)improves soil N status. Its roots system improves soil structure, making it more susceptible to infiltration by water (Orwa et al., 2009). In communal areas of Zimbabwe, it is believed that dryland crop yields increase where sweet thorn has grown and been cleared (Orwa et al., 2009). Sweet thorn extracts water from deep underground, and is thus an indicator for underground water (CABI, 2018; Orwa et al., 2009). The development of its canopy benefits to the grass growing under it, as it reduces the temperatures of the soil and provides shade (Dingaan et al., 2018; Orwa et al., 2009). However, while a low tree density improves grass production, high density (>300 trees/ha) is detrimental to it (Stuart-Hill et al., 1987). Sweet thorn is reported to stabilize sand dunes and disturbed areas (CABI, 2018).
Live fence
A very thorny species, sweet thorn can be used as a living hedge (CABI, 2018).
Bush encroachment and invasiveness
Acacia karroo is a pioneering species prone to be responsible for bush encroachment in grasslands and farming land in South Africa. It may thus be detrimental to grass production because of the competition for soil moisture between grass and trees, decreasing the livestock carrying capacity of grassland. In the Molopo area of South Africa, sweet thorn encroachment may have reduced grass production by 30% (Dingaan et al., 2018).
In Australia, sweet thorn is referred to as a noxious weed, requiring notification and destruction in New South Wales, Western Australia and Queensland (US Forest Service, 2018).