When growing short rotation forest (SRF) crops as a supply of energy, the production and removal of large volumes of biomass from the site will, over time, lead to soil nutrient depletion. It is hence a non-sustainable practice in the longer term. The application of effluent on to SRF crops is a treatment system which, if properly designed and maintained, could both increase the productivity of the biomass crop and reduce the aqueous waste disposal problem. Several waste water land treatment systems are failing due to hydraulic over-loading and poor management causing stress to the trees. Good design and monitoring can influence the success of a system, but there is inadequate information available regarding the role that SRF trees can play. A lysimeter study is described to identify the capacity of selected tree species to take up both water and nutrients. The results will enable better design parameters to be set and over-loading and consequent failure of a system to be avoided.