(1) What is the water usage of the tree species considered as alien invasive species and targeted for eradication by the Working for Water programme; (2) whether research has been conducted into the water use of indigenous trees; if not, why not; (3) whether such research is being conducted or is planned; if so, what has this research shown with regard to the water used by the species studied; (4) why are alien invasive species that are removed not being replaced by appropriate tree species; (5) whether research has been conducted into the effect on global warming when alien invasive species are removed; if not, why not; if so, what are the relevant details of the (a) research and (b) findings?