Acacia saligna (Port Jackson) is one of the most pervasive IAPs in South Africa. The government’s
control efforts have by and large not been co-financed by the private sector due to a lack of incentives.
Here we develop a system dynamics model to assess the costs and benefits of using the invasive Acacia
saligna for the production of wood polymer composites (WPCs). The cumulative net present value for
clearing Acacia saligna and making WPCs amounts to approximately ZAR122.1 million for the
baseline scenario (no WPC production), and is estimated to be ZAR144.4 million for Scenario 2
(WPC production with 20% co-financing), ZAR172.7 million for Scenario 3 (50% co-financing) and
ZAR211.2 million for Scenario 4 (100% co-financing). In addition to these direct financial benefits,
the control of Acacia saligna also offers benefits with respect to employment, an increase in the state’s
tax revenue base, and an increase in the contribution to GDP.