The Economic Implications of Robinia pseudoacacia L. (black locust) on Agricultural Production in South Africa

Robinia pseudoacacia L. (black locust) is an invasive deciduous, broad-leaved tree that has the potential to be widely distributed across South Africa. It has invaded all nine South African provinces. The potential economic impact of R. pseudoacacia on agricultural production stems from the tree’s ability to reduce the carrying capacity for livestock. This study estimated the potential economic implications of R. pseudoacacia on agricultural production in South Africa, specifically the livestock sector. R. pseudoacacia’s potential distribution was calculated by using a maximum-entropy predictive habitat model, MaxEnt. The distribution of livestock, based on grazing capacity (ha/large stock unit) in South Africa, was then determined. The potential direct economic impacts were estimated by assessing the impact of the potential distribution of R. pseudoacacia on the carrying capacity for livestock. The results showed that an infestation of R. pseudoacacia has the potential to reduce the total gross margin in the livestock sector by between approximately R135 million and R674 million, dependent on the level of invasion. The potential levels of foregone income and business activity found in this study reaffirm the need to devote resources to develop a viable, economical and effective control.