Tropical forest ecosystems provide a wide range of benefits to mankind. Economists have categorised these into use and non-use values, further categorised into direct and indirect use on the one hand and option, bequest and existence value on the other. Estimating the 'total economic value' of forests has become a popular topic of research and discussion in the conservation community. Theory and techniques for estimation of the nonuse benefits have dominated recent research. In the process, however, most valuation exercises have overlooked two fundamental issues: a) the 'so what?' problem, i.e. estimating the economic value of something in isolation is not very useful, and b) the 'aggregation problem', i.e. the fact that the supposed 'aggregate social welfare function' has no objective basis. These problems need to be addressed if economic valuation is to provide meaningful and open-minded input" into real-world debates about forest conservation.